ci: Update workflows

.github/workflows/release_aarch64.yml

@@ -16,17 +16,13 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
 
-      - name: Build Docker image
-        uses: docker/build-push-action@v4
-        with:
-          context: .
-          load: true
-          platforms: linux/arm64
-          tags: lablup/backend.ai-hook:latest
+      - name: Pull Docker image
+        run: |
+          docker pull --platform linux/arm64 ubuntu:latest
 
       - name: Build libbaihook
         run: |
-          docker run --rm -v "$(pwd)" lablup/backend.ai-hook:latest /bin/bash -c "./build.sh ${{ matrix.os }}"
+          docker run --rm -v "$(pwd)" ubuntu:latest /bin/bash -c "./build.sh ${{ matrix.os }}"
 
       - name: Release to GitHub
         uses: softprops/action-gh-release@v2