Add docker/setup-buildx-action@v1

.github/workflows/publish_docker_image.yml

@@ -25,6 +25,9 @@ jobs:
         with:
           images: healthchecks/healthchecks
       
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+
       - name: Build and push Docker image
         uses: docker/build-push-action@v2
         with: