Bump MSTest.TestFramework from 3.6.3 to 3.6.4 (#355)

Bumps [MSTest.TestFramework](https://github.com/microsoft/testfx) from 3.6.3 to 3.6.4.
- [Release notes](https://github.com/microsoft/testfx/releases)
- [Changelog](https://github.com/microsoft/testfx/blob/main/docs/Changelog.md)
- [Commits](microsoft/testfx@v3.6.3...v3.6.4)

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

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

Author: dependabot[bot]

Directory.Packages.props

@@ -12,7 +12,7 @@
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
     <PackageVersion Include="Moq" Version="4.20.72" />
     <PackageVersion Include="MSTest.TestAdapter" Version="3.6.4" />
-    <PackageVersion Include="MSTest.TestFramework" Version="3.6.3" />
+    <PackageVersion Include="MSTest.TestFramework" Version="3.6.4" />
     <PackageVersion Include="NonBlocking" Version="2.1.2" />
     <PackageVersion Include="NUnit" Version="4.2.2" />
     <PackageVersion Include="NUnit3TestAdapter" Version="4.6.0" />