limit ghc versions based on fixture support

.github/workflows/test.yml

@@ -49,7 +49,7 @@ jobs:
     needs: core
     strategy:
       matrix:
-        ghc: [ '9.0', '9.2', '9.4' ]
+        ghc: [ '9.0', '9.2' ]
     steps:
     - uses: actions/checkout@v3
     - name: Set up Ruby