Update .NET versions in CI workflow

Comment out the 5.0.x version in the CI configuration.

Author: sdrapkin

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
         uses: actions/setup-dotnet@v5
         with:
           dotnet-version: |
-            5.0.x
+            # 5.0.x
             6.0.x
             7.0.x
             8.0.x