Bump nunit from 3.14.0 to 4.0.0

Bumps [nunit](https://github.com/nunit/nunit) from 3.14.0 to 4.0.0.
- [Release notes](https://github.com/nunit/nunit/releases)
- [Changelog](https://github.com/nunit/nunit/blob/master/CHANGES.md)
- [Commits](nunit/nunit@v3.14.0...v4.0.0)

---
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

@@ -31,7 +31,7 @@
     <PackageReference Include="AltCover" Version="8.6.95" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
-    <PackageReference Include="nunit" Version="3.14.0" />
+    <PackageReference Include="nunit" Version="4.0.0" />
     <PackageReference Include="NUnit.ConsoleRunner" Version="3.16.3" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.5.0">
       <PrivateAssets>all</PrivateAssets>