chore(deps): update .net test stack

Author: renovate[bot]

src/Splat.DependencyInjection.SourceGenerator.Tests/Splat.DependencyInjection.SourceGenerator.Tests.csproj

@@ -8,13 +8,13 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis" Version="4.11.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" PrivateAssets="all" />
     <PackageReference Include="coverlet.msbuild" Version="6.0.4" />
     <PackageReference Include="Verify.SourceGenerators" Version="2.5.0" />
     <PackageReference Include="ReactiveMarbles.SourceGenerator.TestNuGetHelper" Version="1.3.1" />
-    <PackageReference Include="Verify.Xunit" Version="30.7.3" />
+    <PackageReference Include="Verify.Xunit" Version="31.0.0" />
     <PackageRefernece Include="Microsoft.CodeAnalysis.CSharp" Version="4.0.1" PrivateAssets="all" />
   </ItemGroup>