Remove older ghc for macos

Now github actions only supports m1 builds (actions/runner-images#9255)
and older versions of ghc are not compatible with that

The problem is that the version of llvm is too new, we could try
to install an older version of llvm

.github/workflows/macOS.yml

@@ -22,13 +22,10 @@ jobs:
           - macOS
           # - windows
         snapshot:
-          - 'lts-12.11'
-          - 'lts-14.18'
-          - 'lts-16.12'
-          - 'lts-18.28'
-          - 'lts-19.11'
+          - 'lts-19.33'
           - 'lts-20.26'
-          - 'lts-21.6'
+          - 'lts-21.25'
+          - 'lts-22.18'
           - 'nightly'
 
     steps: