Unable to run update script to update PowerShell in manifest

## Steps to reproduce the issue

```
> dotnet run --project .\eng\update-dependencies\ -- 5.0 --product-version powershell=7.1.0-preview.7 --compute-shas
```

## Expected behavior

*Updates manifest*

## Actual behavior

```
update-dependencies Information: 0 : Updating powershell|5.0|build-version
update-dependencies Information: 0 : Updating powershell|5.0|product-version
update-dependencies Information: 0 : Updating powershell|5.0|Linux.Alpine|sha
update-dependencies Information: 0 : Updating powershell|5.0|Linux|arm32|sha
update-dependencies Information: 0 : Updating powershell|5.0|Linux|arm64|sha
update-dependencies Information: 0 : Updating powershell|5.0|Linux|x64|sha
update-dependencies Information: 0 : Updating powershell|5.0|Windows|x64|sha
update-dependencies Information: 0 : Downloading 'https://dotnetclichecksums.blob.core.windows.net:443/tool/7.1.0-preview.7/PowerShell.Linux.Alpine.7.1.0-preview.7.nupkg.sha512'.
update-dependencies Information: 0 : Failed to find `dotnetclichecksums` sha
update-dependencies Information: 0 : Downloading 'https://dotnetcli.blob.core.windows.net/dotnet/checksums/7.1.0-preview.7-sha.txt'.
update-dependencies Information: 0 : Failed to find dotnet release checksums
update-dependencies Information: 0 : Failed to find `PowerShell.Linux.Alpine.7.1.0-preview.7.nupkg` sha
update-dependencies Information: 0 : Downloading 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.Alpine.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Retrieved sha 'c852a06d25e059cc31a0ace87d7738d8390ae7e6b83fd6ba73ef1ae6d1e4258bc436540a3bb309c466c0a9a2c33e9e19797c06e7fa10ba8c381c020430c30169' for 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.Alpine.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Downloading 'https://dotnetclichecksums.blob.core.windows.net:443/tool/7.1.0-preview.7/PowerShell.Linux.arm32.7.1.0-preview.7.nupkg.sha512'.
update-dependencies Information: 0 : Failed to find `dotnetclichecksums` sha
update-dependencies Information: 0 : Failed to find `PowerShell.Linux.arm32.7.1.0-preview.7.nupkg` sha
update-dependencies Information: 0 : Downloading 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.arm32.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Retrieved sha '8cd03689db9c2155616ba93a46d39b7222547d4b3fd8ecc23ccd5691cc65fc04935513ff693d0dba5592899c81cd47c0eb9339f10373db33bf9c5470c2abe7bd' for 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.arm32.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Downloading 'https://dotnetclichecksums.blob.core.windows.net:443/tool/7.1.0-preview.7/PowerShell.Linux.arm64.7.1.0-preview.7.nupkg.sha512'.
update-dependencies Information: 0 : Failed to find `dotnetclichecksums` sha
update-dependencies Information: 0 : Failed to find `PowerShell.Linux.arm64.7.1.0-preview.7.nupkg` sha
update-dependencies Information: 0 : Downloading 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.arm64.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Retrieved sha '36b582be600cf191287fb18599090ea36ab5e8800e099278965c73a465f19716b62458ef122bb91ff89b4f4fbec9f1597dc81a0ece2f852da6572ce3cd87f15e' for 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.arm64.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Downloading 'https://dotnetclichecksums.blob.core.windows.net:443/tool/7.1.0-preview.7/PowerShell.Linux.x64.7.1.0-preview.7.nupkg.sha512'.
update-dependencies Information: 0 : Failed to find `dotnetclichecksums` sha
update-dependencies Information: 0 : Failed to find `PowerShell.Linux.x64.7.1.0-preview.7.nupkg` sha
update-dependencies Information: 0 : Downloading 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.x64.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Retrieved sha '84d5c39a92050576e3b8a650419f43cb222a5d7f4d8fd3b29701a92880be3224d964549de0183f9d46e4d8b2636ffe370af4bbc23267b4194dd5d36f88a3a47f' for 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Linux.x64.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Downloading 'https://dotnetclichecksums.blob.core.windows.net:443/tool/7.1.0-preview.7/PowerShell.Windows.x64.7.1.0-preview.7.nupkg.sha512'.
update-dependencies Information: 0 : Failed to find `dotnetclichecksums` sha
update-dependencies Information: 0 : Failed to find `PowerShell.Windows.x64.7.1.0-preview.7.nupkg` sha
update-dependencies Information: 0 : Downloading 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Windows.x64.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Retrieved sha 'c445ae1ae668c837fb6c05116576118e96b83fca6b7e62cb0303d9cf2a18737c9c4cc9432402ace3be78aba60979e2d0dba3fb209d88a3ab227ece6178b91439' for 'https://pwshtool.blob.core.windows.net/tool/7.1.0-preview.7/PowerShell.Windows.x64.7.1.0-preview.7.nupkg'.
update-dependencies Information: 0 : Executing 'C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\dockerfile-templates\Get-GeneratedDockerfiles.ps1'
ParserError:
Line |
1 | [10:06:04.067] [InstallHandler] No installation found
| ~
| Missing type name after '['.

Failed to update dependencies:
System.AggregateException: One or more errors occurred. (Unable to successfully execute 'C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\dockerfile-templates\Get-GeneratedDockerfiles.ps1')
---> System.InvalidOperationException: Unable to successfully execute 'C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\dockerfile-templates\Get-GeneratedDockerfiles.ps1'
at Dotnet.Docker.ScriptRunnerUpdater.ExecuteScript() in C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\update-dependencies\ScriptRunnerUpdater.cs:line 73
at Dotnet.Docker.ScriptRunnerUpdater.b__4_0() in C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\update-dependencies\ScriptRunnerUpdater.cs:line 45
at Microsoft.DotNet.VersionTools.Dependencies.DependencyUpdateTask.<>c__DisplayClass6_0.<.ctor>b__0() in /_/src/Microsoft.DotNet.VersionTools/lib/src/Dependencies/DependencyUpdateTask.cs:line 32
at System.Threading.Tasks.Task`1.InnerInvoke()
at System.Threading.Tasks.Task.<>c.<.cctor>b__274_0(Object obj)
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location where exception was thrown ---
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
at System.Threading.Tasks.Task`1.get_Result()
at Microsoft.DotNet.VersionTools.Automation.DependencyUpdateUtils.<>c.b__0_0(DependencyUpdateTask task) in /_/src/Microsoft.DotNet.VersionTools/lib/src/Automation/DependencyUpdateUtils.cs:line 29
at System.Linq.Enumerable.SelectEnumerableIterator`2.MoveNext()
at System.Linq.Enumerable.SelectManySingleSelectorIterator`2.MoveNext()
at System.Linq.Set`1.UnionWith(IEnumerable`1 other)
at System.Linq.Enumerable.DistinctIterator`1.FillSet()
at System.Linq.Enumerable.DistinctIterator`1.ToArray()
at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
at Microsoft.DotNet.VersionTools.Automation.DependencyUpdateUtils.Update(IEnumerable`1 updaters, IEnumerable`1 dependencyInfos) in /_/src/Microsoft.DotNet.VersionTools/lib/src/Automation/DependencyUpdateUtils.cs:line 25
at Dotnet.Docker.Program.UpdateFiles(IEnumerable`1 buildInfos) in C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\update-dependencies\Program.cs:line 96
at Dotnet.Docker.Program.Main(String[] args) in C:\Users\Robert Holt\Documents\Dev\Microsoft\dotnet-docker\eng\update-dependencies\Program.cs:line 39
```

## Additional information (e.g. issue happens only occasionally)

## Output of `docker version`

```
Client: Docker Engine - Community
Version: 19.03.12
API version: 1.40
Go version: go1.13.10
Git commit: 48a66213fe
Built: Mon Jun 22 15:43:18 2020
OS/Arch: windows/amd64
Experimental: false
error during connect: Get http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.40/version: open //./pipe/docker_engine: The system cannot find the file specified. In the default daemon configuration on Windows, the docker client must be run elevated to connect. This error may also indicate that the docker daemon is not running.
```

## Output of `docker info`

```
Client:
Debug Mode: false

Server:
ERROR: error during connect: Get http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.40/info: open //./pipe/docker_engine: The system cannot find the file specified. In the default daemon configuration on Windows, the docker client must be run elevated to connect. This error may also indicate that the docker daemon is not running.
errors pretty printing info
```