Bump Microsoft.NET.Test.Sdk from 16.8.0 to 16.8.3
Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.8.0 to 16.8.3.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](https://github.com/microsoft/vstest/compare/v16.8.0...v16.8.3)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>