Merge pull request #94 from swoolcock/dependabot/nuget/NUnit-3.13.0

Bump NUnit from 3.12.0 to 3.13.0

Author: swoolcock

osu.Game.Rulesets.Rush.Tests/osu.Game.Rulesets.Rush.Tests.csproj

@@ -11,7 +11,7 @@
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
-    <PackageReference Include="NUnit" Version="3.12.0" />
+    <PackageReference Include="NUnit" Version="3.13.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.17.0" />
   </ItemGroup>
   <ItemGroup>