Bump MSTest.TestAdapter from 2.2.8 to 3.1.1

Bumps [MSTest.TestAdapter](https://github.com/microsoft/testfx) from 2.2.8 to 3.1.1.
- [Release notes](https://github.com/microsoft/testfx/releases)
- [Changelog](https://github.com/microsoft/testfx/blob/main/docs/Changelog.md)
- [Commits](microsoft/testfx@v2.2.8...v3.1.1)

---
updated-dependencies:
- dependency-name: MSTest.TestAdapter
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

tests/Shared.LibraryTests/Shared.LibraryTests.csproj

@@ -6,7 +6,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.2" />
-		<PackageReference Include="MSTest.TestAdapter" Version="2.2.8" />
+		<PackageReference Include="MSTest.TestAdapter" Version="3.1.1" />
 		<PackageReference Include="MSTest.TestFramework" Version="3.1.1" />
 		<PackageReference Include="coverlet.collector" Version="6.0.0" />
 	</ItemGroup>