Add new workflow with automatic GHC matrix generation

.github/workflows/main.yml

@@ -0,0 +1,72 @@
+name: CI
+on:
+  pull_request:
+    branches:
+      - master
+  push:
+    branches:
+      - master
+
+concurrency:
+  group: build-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  generate-ghc-matrix:
+    name: "Generate GHC matrix from .cabal file"
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Extract the tested-with GHC versions
+        id: set-matrix
+        uses: kleidukos/[email protected]
+        with:
+          cabal-file: cassava-megaparsec.cabal
+          ubuntu: true
+          version: 0.1.6.0
+
+  build:
+    name: GHC ${{ matrix.ghc }} on ${{ matrix.os }}
+    needs: generate-ghc-matrix
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix: ${{ fromJSON(needs.generate-ghc-matrix.outputs.matrix) }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Setup Haskell tools
+        uses: haskell-actions/setup@v2
+        id: setup
+        with:
+          ghc-version: ${{ matrix.ghc }}
+          cabal-version: 'latest'
+          cabal-update: true
+      - name: Configure the build
+        run: |
+          cabal configure --enable-tests --disable-documentation
+          cabal build all --dry-run
+      - name: Restore cached dependencies
+        uses: actions/cache/restore@v4
+        id: cache
+        env:
+          key: ${{ runner.os }}-ghc-${{ steps.setup.outputs.ghc-version }}-cabal-${{ steps.setup.outputs.cabal-version }}
+        with:
+          path: ${{ steps.setup.outputs.cabal-store }}
+          key: ${{ env.key }}-plan-${{ hashFiles('**/plan.json') }}
+          restore-keys: ${{ env.key }}-
+      - name: Install dependencies
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: cabal build all --only-dependencies
+      - name: Save cached dependencies
+        uses: actions/cache/save@v4
+        if: steps.cache.outputs.cache-hit != 'true'
+        with:
+          path: ${{ steps.setup.outputs.cabal-store }}
+          key: ${{ steps.cache.outputs.cache-primary-key }}
+      - name: Build
+        run: cabal build all
+      - name: Run tests
+        run: cabal test all
+        env:
+          ROLLBAR_TOKEN: ${{ secrets.ROLLBAR_TOKEN }}