chore: update dependency xunit.combinatorial to v2

Author: renovate-bot

Google.Cloud.EntityFrameworkCore.Spanner.Tests/Google.Cloud.EntityFrameworkCore.Spanner.Tests.csproj

@@ -25,7 +25,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Proxies" Version="8.0.18" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1" />
     <PackageReference Include="xunit" Version="2.9.3" />
-    <PackageReference Include="Xunit.Combinatorial" Version="1.6.24" />
+    <PackageReference Include="Xunit.Combinatorial" Version="2.0.24" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.3" />
   </ItemGroup>