chore(deps): bump MSTest.TestFramework from 3.6.3 to 3.6.4 (#542)

Author: dependabot[bot]

Directory.Packages.props

@@ -19,7 +19,7 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="Microsoft.TestPlatform.TestHost" Version="17.12.0" />
     <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="NUnit" Version="4.2.2" />
     <PackageVersion Include="NUnit3TestAdapter" Version="4.6.0" />
     <PackageVersion Include="NUnit.Analyzers" Version="4.4.0" />