Update dependency xUnit.v3 to v3

Author: renovate[bot]

test/Soenneker.Utils.AsyncSingleton.Tests/Soenneker.Utils.AsyncSingleton.Tests.csproj

@@ -17,7 +17,7 @@
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>
         <PackageReference Include="Soenneker.Tests.Unit" Version="3.0.866" />
-        <PackageReference Include="xUnit.v3" Version="2.0.3" />
+        <PackageReference Include="xUnit.v3" Version="3.0.0" />
     </ItemGroup>
 
     <ItemGroup>