chore(deps): update mstest monorepo to 4.2.1

Author: renovate[bot]

Csv.Tests/Csv.Tests.csproj

@@ -21,8 +21,8 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
-    <PackageReference Include="MSTest.TestFramework" Version="4.0.2" />
-    <PackageReference Include="MSTest.TestAdapter" Version="4.0.2" />
+    <PackageReference Include="MSTest.TestFramework" Version="4.2.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="4.2.1" />
   </ItemGroup>
 
 </Project>