add CI workflow

.github/workflows/haskell.yaml

@@ -0,0 +1,43 @@
+name: Haskell CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Cache Stack
+      id: cache-stack-unix
+      uses: actions/cache@v3
+      with:
+        path: ~/.stack
+        key: ubuntu-latest-stack-home-${{ hashFiles('stack.yaml') }}-${{ hashFiles('package.yaml') }}
+
+    - name: Setup stack
+      uses: haskell/actions/setup@v1
+      with:
+        enable-stack: true
+        stack-no-global: true
+
+
+    - name: Install dependencies
+      run: |
+        set -ex
+        stack --no-terminal --install-ghc test --bench --only-dependencies
+        set +ex
+
+    - name: Build
+      run: |
+        set -ex
+        stack --no-terminal $ARGS test --bench --no-run-benchmarks --haddock --no-haddock-deps
+        set +ex