chore: Use Docker Buildx to cache Docker layers

.github/workflows/ci-backend.yml

@@ -14,7 +14,7 @@ jobs:
     name: Test Backend
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Run Backend Tests
         run: sudo docker-compose --env-file .env-github-actions run server bash -c "coverage run manage.py test"
       - name: Generate Backend Coverage Report (Inline)
@@ -57,7 +57,20 @@ jobs:
     name: Lint Backend
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Cache Docker layers
+        uses: docker/bake-action@master
+        with:
+          push: false
+          load: true
+          files: |-
+            docker-compose.yaml
+            docker-compose-cache.json
+
       - name: Lint Backend
         continue-on-error: false
         run: sudo docker-compose --env-file .env-github-actions run server bash -c "flake8"