chore(deps): Bump Verify.XUnit from 28.6.0 to 28.8.1

Bumps [Verify.XUnit](https://github.com/VerifyTests/Verify) from 28.6.0 to 28.8.1.
- [Release notes](https://github.com/VerifyTests/Verify/releases)
- [Commits](https://github.com/VerifyTests/Verify/commits)

---
updated-dependencies:
- dependency-name: Verify.XUnit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

test/Directory.Build.props

@@ -27,7 +27,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Meziantou.Xunit.ParallelTestFramework" Version="2.3.0"/>
-    <PackageReference Include="Verify.XUnit" Version="28.6.0" />
+    <PackageReference Include="Verify.XUnit" Version="28.8.1" />
     <PackageReference Include="Verify.DiffPlex" Version="3.1.2" />
     <PackageReference Include="JunitXml.TestLogger" Version="4.1.0" />
     <PackageReference Include="NSubstitute" Version="5.3.0" />