CI: no need to restore cache before setup-haskell

undo 6bd17fc from #8844; the change was made in response to an issue
that was later fixed on the haskell/action side

(cherry picked from commit 3b8e6e9)

# Conflicts:
#	.github/workflows/validate.yml

.github/workflows/validate.yml

@@ -238,6 +238,7 @@ jobs:
 
       - uses: actions/checkout@v3
 
+<<<<<<< HEAD
 <<<<<<< HEAD
 =======
       #  See the following link for a breakdown of the following step
@@ -254,6 +255,8 @@ jobs:
           restore-keys: ${{ runner.os }}-${{ matrix.ghc }}-20220419-
 
 >>>>>>> 4f5835509 (CI: no need to exclude caching on Windows anymore)
+=======
+>>>>>>> 3b8e6e9bf (CI: no need to restore cache before setup-haskell)
       # See https://github.com/haskell/cabal/pull/8739
       - name: Sudo chmod to permit ghcup to update its cache
         run: |
@@ -293,6 +296,17 @@ jobs:
         run: |
           git config --global protocol.file.allow always
 
+      #  See the following link for a breakdown of the following step
+      #  https://github.com/haskell/actions/issues/7#issuecomment-745697160
+      - uses: actions/cache@v3
+        with:
+          # validate.sh uses a special build dir
+          path: |
+            ${{ steps.setup-haskell.outputs.cabal-store }}
+            dist-*
+          key: ${{ runner.os }}-${{ matrix.ghc }}-20220419-${{ github.sha }}
+          restore-keys: ${{ runner.os }}-${{ matrix.ghc }}-20220419-
+
       # The '+exe' constraint below is important, otherwise cabal-install
       # might decide to build the library but not the executable which is
       # what we need.
@@ -410,7 +424,11 @@ jobs:
         id: setup-haskell
         with:
           ghc-version: ${{ matrix.ghc }}
+<<<<<<< HEAD
           cabal-version: '3.8.1.0'
+=======
+          cabal-version: latest # latest is mandatory for cabal-testsuite, see https://github.com/haskell/cabal/issues/8133
+>>>>>>> 3b8e6e9bf (CI: no need to restore cache before setup-haskell)
 
       # As we are reusing the cached build dir from the previous step
       # the generated artifacts are available here,