Update dependency NSubstitute to v6

Author: renovate[bot]

Preagonal.Scripting.GS2Engine.TestApp/Preagonal.Scripting.GS2Engine.TestApp.csproj

@@ -22,7 +22,7 @@
 
 	<ItemGroup>
 	  <PackageReference Include="GS2Compiler" Version="1.1.4" />
-	  <PackageReference Include="NSubstitute" Version="5.3.0" />
+	  <PackageReference Include="NSubstitute" Version="6.0.0" />
 	  <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
 	  <PackageReference Include="xunit" Version="2.9.3" />
 	</ItemGroup>