Bump Verify.XUnit from 28.7.1 to 28.8.1 in the verify group (#178)

Bumps the verify group with 1 update: [Verify.XUnit](https://github.com/VerifyTests/Verify).


Updates `Verify.XUnit` from 28.7.1 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
  dependency-group: verify
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/Aviationexam.GeneratedJsonConverters.SourceGenerator.Tests/Aviationexam.GeneratedJsonConverters.SourceGenerator.Tests.csproj

@@ -23,7 +23,7 @@
     <PackageReference Include="System.Net.Http" Version="4.3.4" />
     <PackageReference Include="System.Text.Json" Version="9.0.0" />
     <PackageReference Include="System.Text.RegularExpressions" Version="4.3.1" />
-    <PackageReference Include="Verify.XUnit" Version="28.7.1" />
+    <PackageReference Include="Verify.XUnit" Version="28.8.1" />
     <PackageReference Include="Verify.SourceGenerators" Version="2.5.0" />
     <PackageReference Include="xunit" Version="2.9.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.0.0">