Bump Microsoft.NET.Test.Sdk from 17.11.1 to 17.12.0 in /src (#572)

Author: dependabot[bot]

src/Directory.Packages.props

@@ -9,7 +9,7 @@
     <PackageVersion Include="EmptyFiles" Version="8.5.1" />
     <PackageVersion Include="Fody" Version="6.9.0" />
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="27.0.2" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="Polyfill" Version="7.4.1" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.144" />
     <PackageVersion Include="Resourcer.Fody" Version="1.8.1" />