chore(deps): update dependency microsoft.net.test.sdk to 17.12.0

Author: renovate[bot]

src/ReactiveUI.Validation.Tests/ReactiveUI.Validation.Tests.csproj

@@ -10,7 +10,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="xunit" Version="2.9.2" />
     <PackageReference Include="xunit.runner.console" Version="2.9.2" />
     <PackageReference Include="Xunit.StaFact" Version="1.1.11" />