add GHC 9.0 support

.github/workflows/Cabal-Linux.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ghc: [ "8.10", "8.6" ]
+        ghc: [ "9.0", "8.8" ]
     steps:
 
       - name: "Git checkout"
@@ -62,9 +62,9 @@ jobs:
         run: cabal v2-test $cabalConfig
 
       - name: "Haddock"
-        if: ${{ matrix.ghc == '8.10' }}
+        if: ${{ matrix.ghc == '9.0' }}
         run: cabal v2-haddock $cabalConfig
 
       - name: "Source distribution file"
-        if: ${{ matrix.ghc == '8.10' }}
+        if: ${{ matrix.ghc == '9.0' }}
         run: cabal v2-sdist

.github/workflows/Cabal-macOS.yml

@@ -15,11 +15,11 @@ jobs:
 
   build10:
     name: "GHC"
-    runs-on: macOS-latest
+    runs-on: macos-latest
     strategy:
       matrix:
         # It is dev env, so trying to stick to last GHC.
-        ghc: [ "8.10" ]
+        ghc: [ "9.0" ]
     steps:
 
       - name: "Git checkout"

.github/workflows/On-Release-Cabal-Linux.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         # Since CI by default tests boundary GHCs, test middle versions of GHCs
-        ghc: [ "8.8" ]
+        ghc: [ "9.0" ]
     steps:
       - name: "Git checkout"
         uses: actions/checkout@v2