Bump Verify.Xunit from 19.11.2 to 19.12.0 in /eng/dependabot (#31576)

Author: marcpopMSFT

eng/dependabot/Packages.props

@@ -4,7 +4,7 @@
 
   <ItemGroup>
     <!--Test dependencies-->
-    <PackageReference Update="Verify.Xunit" Version="19.11.2" />
+    <PackageReference Update="Verify.Xunit" Version="19.12.0" />
     <PackageReference Update="Verify.DiffPlex" Version="2.2.0" />
     <PackageReference Update="FakeItEasy" Version="7.3.1" />
     <PackageReference Update="Wcwidth.Sources" Version="1.0.0" />