Bump NUnit from 3.13.3 to 4.1.0

Bumps NUnit from 3.13.3 to 4.1.0.

---
updated-dependencies:
- dependency-name: NUnit
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

UnitTests/UnitTests.csproj

@@ -14,7 +14,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.2" />
-    <PackageReference Include="NUnit" Version="3.13.3" />
+    <PackageReference Include="NUnit" Version="4.1.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
     <PackageReference Include="NUnit.Analyzers" Version="3.10.0">
       <PrivateAssets>all</PrivateAssets>