Update dependency Verify.Xunit to v28 (#770)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Cake.Issues.PullRequests.Tests/Cake.Issues.PullRequests.Tests.csproj

@@ -5,7 +5,7 @@
   <ItemGroup>
     <PackageReference Include="Spectre.Console" Version="0.47.0" />
     <PackageReference Include="Spectre.Console.Testing" Version="0.47.0" />
-    <PackageReference Include="Verify.Xunit" Version="27.1.0" />
+    <PackageReference Include="Verify.Xunit" Version="28.0.0" />
   </ItemGroup>
 
    <ItemGroup>