Bump NUnit and System.Threading.Tasks.Extensions

Bumps [NUnit](https://github.com/nunit/nunit) and System.Threading.Tasks.Extensions. These dependencies needed to be updated together.

Updates `NUnit` from 4.2.2 to 4.3.0
- [Release notes](https://github.com/nunit/nunit/releases)
- [Changelog](https://github.com/nunit/nunit/blob/main/CHANGES.md)
- [Commits](nunit/nunit@4.2.2...4.3.0)

Updates `System.Threading.Tasks.Extensions` from 4.6.0 to 4.5.4

---
updated-dependencies:
- dependency-name: NUnit
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: System.Threading.Tasks.Extensions
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

tests/NHapi.Base.NUnit/NHapi.Base.NUnit.csproj

@@ -16,7 +16,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="NUnit" Version="4.2.2" />
+    <PackageReference Include="NUnit" Version="4.3.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="TimeZoneConverter" Version="6.1.0" />