Remove sourcelink package dependency

.NET SDK 8 contains sourcelink tooling. All repos that consume .NET SDK 8 and newer Arcade package are getting this dependency removed right now.

Please remove `sourcelink` package dependency once this repo is updated to use .NET SDK 8 and newer Arcade package.

Here's the sourcelink package dependency that needs to be removed:

https://github.com/dotnet/command-line-api/blob/a045dd54a4c44723c215d992288160eb1401bb7f/eng/Version.Details.xml#L16-L20

The following should also be removed at the same time:

https://github.com/dotnet/command-line-api/blob/a045dd54a4c44723c215d992288160eb1401bb7f/eng/Versions.props#L36