chore: add a dedicated GitHub action job to test armhf build, hoping for some upstream fix

.github/workflows/continuous_integration.yml

@@ -68,4 +68,28 @@ jobs:
       - name: Build and push Docker image for main branch
         run: |
           make release GOTENBERG_VERSION=edge
-          make release GOTENBERG_VERSION=edge DOCKER_REPOSITORY=thecodingmachine
+          make release GOTENBERG_VERSION=edge DOCKER_REPOSITORY=thecodingmachine
+
+  # FIXME: temporary job for checking if armhf build is working thanks to an upstream fix.
+  armhf_build:
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    continue-on-error: true
+    needs:
+      - Tests
+    name: armhf build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Checkout source code
+        uses: actions/checkout@v4
+      - name: Log in to Docker Hub Container Registry
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Build try of armhf Docker image variant
+        run: |
+          make release GOTENBERG_VERSION=armmhf