Support sparse checkout repositories

[pakrym]

See https://github.blog/2020-01-17-bring-your-monorepo-down-to-size-with-sparse-checkout/

Currently the build inside a sparse checkout fails with:

D:\a\_work\1\.nuget\packages\microsoft.build.tasks.git\1.1.1\build\Microsoft.Build.Tasks.Git.targets(25,5): error : Error reading git repository information: Unsupported repository version 1. Only versions up to 0 are supported. [D:\a\_work\1\s\sdk\core\Azure.Core.Amqp\src\Azure.Core.Amqp.csproj]
D:\a\_work\1\.nuget\packages\microsoft.build.tasks.git\1.1.1\build\Microsoft.Build.Tasks.Git.targets(25,5): error : Unable to locate repository with working directory that contains directory 'D:\a\_work\1\s\sdk\core\Azure.Core.Amqp\src'. [D:\a\_work\1\s\sdk\core\Azure.Core.Amqp\src\Azure.Core.Amqp.csproj]
D

[lostmsu]

This is a problem for any packages exposed to Python with .NET component in them: pip, the most commonly used Python package manager, does partial clones, which also use "version 1".

[hcoona]

Hit this issue from using Scalar.

[sliekens]

@tmat any chance you could create a release with this change? I want to use partial clones but this fix is not live so I am hitting a wall.

/github/home/.nuget/packages/microsoft.build.tasks.git/1.1.1/build/Microsoft.Build.Tasks.Git.targets(25,5): error : Error reading git repository information: Unsupported repository version 1. Only versions up to 0 are supported. [/__w/gw2sdk/gw2sdk/GW2SDK/GW2SDK.csproj::TargetFramework=netstandard2.0]
/github/home/.nuget/packages/microsoft.build.tasks.git/1.1.1/build/Microsoft.Build.Tasks.Git.targets(25,5): warning : Unable to locate repository with working directory that contains directory '/__w/gw2sdk/gw2sdk/GW2SDK'. [/__w/gw2sdk/gw2sdk/GW2SDK/GW2SDK.csproj::TargetFramework=netstandard2.0]