Add multi-arch support (#83)

.github/workflows/main.yml

@@ -26,10 +26,15 @@ jobs:
             type=ref,event=pr
             type=sha
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
 
       - name: Login to DockerHub
+        # Forks don't have push access to docker
+        if: github.repository == 'caddyserver/ingress'
         uses: docker/login-action@v1
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
@@ -39,9 +44,10 @@ jobs:
         id: docker_build
         uses: docker/build-push-action@v2
         with:
-          push: true
+          push: ${{ github.repository == 'caddyserver/ingress' }}
           tags: ${{ steps.docker_meta.outputs.tags }}
           labels: ${{ steps.docker_meta.outputs.labels }}
+          platforms: linux/amd64,linux/arm64
           cache-from: type=gha
           cache-to: type=gha,mode=max
 
@@ -99,6 +105,8 @@ jobs:
 
       - name: Set current image tag
         working-directory: charts/caddy-ingress-controller
+        # Forks don't have push access to docker so don't use it in tests
+        if: github.repository == 'caddyserver/ingress'
         run: envsubst < ci/test-values.yaml.tpl > ci/test-values.yaml
         env:
           TAG: ${{ steps.image-tag.outputs.data }}