Bump Microsoft.NET.Test.Sdk from 16.7.1 to 16.8.3 (#2032)
Bump Microsoft.NET.Test.Sdk from 16.7.1 to 16.8.3 (#2032)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.7.1 to 16.8.3.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](https://github.com/microsoft/vstest/compare/v16.7.1...v16.8.3)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

Co-authored-by: dependabot[bot] <1c358da00a777d4e9898c1280ab801e2df165188@users.noreply.github.com>
graphql-dotnet/graphql-dotnet,joemcbride/graphql-dotnet,joemcbride/graphql-dotnet,graphql-dotnet/graphql-dotnet,graphql-dotnet/graphql-dotnet