Add GHA for hadolint (#54)

* Add GHA for `hadolint`

* Update main.yml

.github/workflows/main.yml

@@ -32,6 +32,22 @@ jobs:
       - name: Build Docker image
         run: make docker-build
 
+  hadolint:
+    name: hadolint
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Dockerfile linter
+        uses: hadolint/hadolint-action@v3.1.0
+        # For now, ignoring:
+        # DL3008 warning: Pin versions in apt get install (e.g., apt-get install <package>=<version>); and
+        # DL3018 warning: Pin versions in apk add (e.g., apk add <package>=<version>)
+        with:
+          dockerfile: Dockerfile
+          ignore: DL3008,DL3018
+
   license-check:
     runs-on: ubuntu-latest
     steps: