Unable to run on macOS when .net core 3.0 is installed

I'm getting an error when trying to run this on macOS. I have .net core 3.0 installed, not sure if that is causing this or not. If so, you should be able to solve with a `global.json` file.

### This issue is for a: (mark with an `x`)
```
- [x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
>
1. Clone sample
1. `dotnet build`
1. `dotnet run`

### OS and Version?
macOS Mojave 10.14.5

### Error message on `dotnet run`

```
PS /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api> dotnet build
Microsoft (R) Build Engine version 16.3.0-preview-19377-01+dd8019d9e for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

Restore completed in 570.63 ms for /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api/TodoApi.csproj.
Restore completed in 859.64 ms for /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api/TodoApi.csproj.
You are using a preview version of .NET Core. See: https://aka.ms/dotnet-core-preview
TodoApi -> /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api/bin/Debug/netcoreapp2.0/TodoApi.dll

Build succeeded.
0 Warning(s)
0 Error(s)

Time Elapsed 00:00:05.73
PS /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api> dotnet run

Unhandled Exception: System.InvalidOperationException: HTTPS endpoints can only be configured using KestrelServerOptions.Listen().
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.AddressesStrategy.d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServer.d__21`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Hosting.Internal.WebHost.d__26.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Hosting.WebHostExtensions.d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Hosting.WebHostExtensions.d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Hosting.WebHostExtensions.Run(IWebHost host)
at TodoApi.Program.Main(String[] args) in /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api/Program.cs:line 18
```

### dotnet info

```
PS /Users/sayedhashimi/data/mycode/OSS/dotnet-core-api> dotnet --info
.NET Core SDK (reflecting any global.json):
Version: 3.0.100-preview8-013656
Commit: 8bf06ffc8d

Runtime Environment:
OS Name: Mac OS X
OS Version: 10.14
OS Platform: Darwin
RID: osx.10.14-x64
Base Path: /usr/local/share/dotnet/sdk/3.0.100-preview8-013656/

Host (useful for support):
Version: 3.0.0-preview8-28405-07
Commit: d01b2fb7bc

.NET Core SDKs installed:
1.1.14 [/usr/local/share/dotnet/sdk]
2.1.2 [/usr/local/share/dotnet/sdk]
2.1.400 [/usr/local/share/dotnet/sdk]
2.1.700 [/usr/local/share/dotnet/sdk]
2.2.300 [/usr/local/share/dotnet/sdk]
3.0.100-preview8-013656 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.11 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.11 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0-preview8.19405.7 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 1.0.16 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.13 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.11 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0-preview8-28405-07 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
```