Bump MSTest.TestFramework from 4.1.0 to 4.2.1 (#118)

---
updated-dependencies:
- dependency-name: MSTest.TestFramework
  dependency-version: 4.2.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Directory.Packages.props

@@ -9,7 +9,7 @@
   <ItemGroup>
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
     <PackageVersion Include="MSTest.TestAdapter" Version="4.1.0" />
-    <PackageVersion Include="MSTest.TestFramework" Version="4.1.0" />
+    <PackageVersion Include="MSTest.TestFramework" Version="4.2.1" />
     <PackageVersion Include="System.CodeDom" Version="10.0.5" />
   </ItemGroup>
 </Project>