Bump Gherkin from 27.0.0 to 28.0.0 in /src

Bumps [Gherkin](https://github.com/cucumber/gherkin) from 27.0.0 to 28.0.0.
- [Release notes](https://github.com/cucumber/gherkin/releases)
- [Changelog](https://github.com/cucumber/gherkin/blob/main/CHANGELOG.md)
- [Commits](cucumber/gherkin@v27.0.0...v28.0.0)

---
updated-dependencies:
- dependency-name: Gherkin
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

src/NGherkin/NGherkin.csproj

@@ -2,7 +2,7 @@
   <Import Project="../Package.props" />
 
   <ItemGroup>
-    <PackageReference Include="Gherkin" Version="27.0.0" />
+    <PackageReference Include="Gherkin" Version="28.0.0" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
   </ItemGroup>