Add docker login action

.github/workflows/lint.yml

@@ -5,6 +5,12 @@ jobs:
     name: Lint Lua Scripts
     runs-on: ubuntu-latest
     steps:
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v1
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
       - name: Checkout
         uses: actions/checkout@v2
       - name: Lint