Bump Verify.Xunit from 28.2.0 to 28.8.1

Bumps [Verify.Xunit](https://github.com/VerifyTests/Verify) from 28.2.0 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]>

Author: dependabot[bot]

test/BenchmarkDotNetVisualizer.Tests/BenchmarkDotNetVisualizer.Tests.csproj

@@ -13,7 +13,7 @@
     <PackageReference Include="xunit" Version="2.9.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" PrivateAssets="All" />
     <PackageReference Include="Verify.DiffPlex" Version="3.1.2" />
-    <PackageReference Include="Verify.Xunit" Version="28.2.0" />
+    <PackageReference Include="Verify.Xunit" Version="28.8.1" />
   </ItemGroup>
 
   <ItemGroup>