build(deps): Bump NUnit from 4.2.0 to 4.2.1 in the all group

Bumps the all group with 1 update: [NUnit](https://github.com/nunit/nunit).


Updates `NUnit` from 4.2.0 to 4.2.1
- [Release notes](https://github.com/nunit/nunit/releases)
- [Changelog](https://github.com/nunit/nunit/blob/main/CHANGES.md)
- [Commits](nunit/nunit@4.2.0...4.2.1)

---
updated-dependencies:
- dependency-name: NUnit
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: all
...

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

src/Directory.Packages.props

@@ -42,7 +42,7 @@
     <PackageVersion Include="Npgsql" Version="8.0.3" />
     <PackageVersion Include="OpenSearch.Client" Version="1.7.1" />
     <PackageVersion Include="Pgvector" Version="0.2.0" />
-    <PackageVersion Include="NUnit" Version="4.2.0" />
+    <PackageVersion Include="NUnit" Version="4.2.1" />
     <PackageVersion Include="NUnit3TestAdapter" Version="4.6.0" />
     <PackageVersion Include="PolySharp" Version="1.14.1">
       <PrivateAssets>all</PrivateAssets>