Added multi arch step

Signed-off-by: Nicholas Bucher <[email protected]>

Author: Charlesthebird

.github/workflows/release.yaml

@@ -67,6 +67,6 @@ jobs:
 
       - name: Build and push Docker image
         run: |
-          docker build --tag gcr.io/solo-public/docs/portal-frontend:${RELEASE_TAG} --tag gcr.io/solo-public/docs/portal-frontend:latest .
+          docker buildx build --platform linux/amd64,linux/arm64 --tag gcr.io/solo-public/docs/portal-frontend:${RELEASE_TAG} --tag gcr.io/solo-public/docs/portal-frontend:latest .
           docker push gcr.io/solo-public/docs/portal-frontend:${RELEASE_TAG}
           docker push gcr.io/solo-public/docs/portal-frontend:latest