(wip) ci: Add haskell-ci-regenerate workflow

.github/workflows/haskell-ci-regenerate.yml

@@ -0,0 +1,62 @@
+name: Haskell-CI regenerate
+
+on:
+  workflow_dispatch:
+  push:  # FIXME: drop
+
+jobs:
+  haskell-ci-regenerate:
+    name: Haskell-CI regenerate
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Clone project
+        uses: actions/checkout@v3
+        with:
+          path: project
+
+      - name: Clone haskell-ci
+        uses: actions/checkout@v3
+        with:
+          repository: haskell-CI/haskell-ci
+          path: haskell-ci
+
+      - name: Get haskell-ci version
+        id: haskell-ci-version
+        working-directory: haskell-ci
+        run: |
+          { echo -n version=; git rev-parse HEAD; } >> $GITHUB_OUTPUT
+
+      - name: Setup Haskell
+        id: setup
+        uses: haskell/actions/setup@v2
+        with:
+          ghc-version: 9.4
+
+      - name: Cache cabal store
+        uses: actions/cache@v3
+        with:
+          path: ${{ steps.setup.outputs.cabal-store }}
+          key: cabal-store-${{ runner.os }}-ghc-${{ steps.setup.outputs.ghc-version }}-cabal-${{ steps.setup.outputs.cabal-version }}-haskell-ci-${{ steps.haskell-ci-version.outputs.version }}
+          restore-keys: |
+            cabal-store-${{ runner.os }}-ghc-${{ steps.setup.outputs.ghc-version }}-cabal-${{ steps.setup.outputs.cabal-version }}-
+
+      - name: Install haskell-ci
+        working-directory: haskell-ci
+        run: |
+          cabal install
+
+      - name: Regenerate haskell-ci
+        working-directory: project
+        run: |
+          haskell-ci regenerate
+
+      - name: Commit/push if changed
+        working-directory: project
+        run: |
+          set -ex
+          git config user.name 'github-actions[bot]'
+          git config user.email '41898282+github-actions[bot]@users.noreply.github.com'
+          git diff --quiet --exit-code && exit
+          git commit -a -m 'man: Update'
+          git push