Bump NUnit3TestAdapter from 4.0.0 to 4.2.1

Bumps [NUnit3TestAdapter](https://github.com/nunit/nunit3-vs-adapter) from 4.0.0 to 4.2.1.
- [Release notes](https://github.com/nunit/nunit3-vs-adapter/releases)
- [Commits](nunit/nunit3-vs-adapter@V4.0.0...V4.2.1)

---
updated-dependencies:
- dependency-name: NUnit3TestAdapter
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

src/Stravaig.Configuration.Diagnostics.Tests/Stravaig.Configuration.Diagnostics.Tests.csproj

@@ -8,7 +8,7 @@
 
     <ItemGroup>
         <PackageReference Include="nunit" Version="3.13.2" />
-        <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+        <PackageReference Include="NUnit3TestAdapter" Version="4.2.1" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
         <PackageReference Include="Serilog" Version="2.10.0" />
         <PackageReference Include="Serilog.Extensions.Logging" Version="3.1.0" />