amd64 image binding

.woodpecker/frontend.yml

@@ -4,6 +4,9 @@ matrix:
       FRONTEND_DOCKERFILE: ci/prod/compose/frontend.dockerfile
       FRONTEND_ENV: prod
 
+labels:
+  platform: linux/amd64
+
 when:
   - event: push
     branch: main
@@ -54,6 +57,7 @@ steps:
     image: gcr.io/kaniko-project/executor:debug
     depends_on: [ version, secrets ]
     commands:
+      - '[ "$(uname -m)" = "x86_64" ] || { echo "image build requires an amd64 runner"; exit 1; }'
       - sh ci/scripts/frontend/build-image.sh
 
   - name: deploy