deps: update vstest monorepo to 17.12.0

Author: renovate[bot]

Directory.Packages.props

@@ -3,8 +3,8 @@
   <ItemGroup>
     <PackageVersion Include="Expecto" Version="[10.0, 11.0)" />
     <PackageVersion Include="FSharp.Core" Version="[7.0.200,)" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
-    <PackageVersion Include="Microsoft.TestPlatform.ObjectModel" Version="17.11.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageVersion Include="Microsoft.TestPlatform.ObjectModel" Version="17.12.0" />
     <PackageVersion Include="System.Collections.Immutable" Version="[6.0.1,)" />
   </ItemGroup>