feat: add hadolint

.github/workflows/lint.yml

@@ -0,0 +1,46 @@
+name: Lint Dockerfile
+on:
+  workflow_dispatch:
+  pull_request:
+  push:
+    paths:
+      - "Dockerfile.template"
+
+jobs:
+  lint:
+    name: 'Lint Dockerfile (PHP: ${{ matrix.php-version }})'
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        php-version:
+          - '8.0'
+          - '8.1'
+          - '8.2'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Lint Dockerfile
+        uses: hadolint/hadolint-action@master
+        with:
+          dockerfile: ./${{ matrix.php-version }}/Dockerfile
+
+      - name: Update Pull Request
+        uses: actions/github-script@v6
+        if: github.event_name == 'pull_request'
+        with:
+          script: |
+            const output = `
+            #### Hadolint: \`${{ steps.hadolint.outcome }}\`
+            \`\`\`
+            ${process.env.HADOLINT_RESULTS}
+            \`\`\`
+            `;
+
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: output
+            })