Update dependency NUnit to v3.13.0

Author: renovate-bot

src/OpenInApp.Common.Tests/OpenInApp.Common.Tests.csproj

@@ -162,7 +162,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="NUnit">
-      <Version>3.6.1</Version>
+      <Version>3.13.0</Version>
     </PackageReference>
     <PackageReference Include="NUnit.Console">
       <Version>3.6.1</Version>