Add arm64 image build capability

.gitlab/ci/custom.images.yml

@@ -8,6 +8,7 @@
       docker buildx build \
         --cache-to=type=inline \
         --cache-from="$CI_REGISTRY_IMAGE:$1" \
+        --platform=linux/${ARCH:-amd64} \
         --push="${PUSH_CUSTOM_IMAGE:-false}" \
         --label "ci_pipeline_url=$CI_PIPELINE_URL" \
         --label "ci_job_url=$CI_JOB_URL" \

.gitlab/ci/definitions.yml

@@ -1,6 +1,16 @@
 .build_and_push:
   stage: custom
   needs: []
+  variables:
+    QEMU_IMAGE: tonistiigi/binfmt:qemu-v6.2.0
+  before_script:
+    - |
+      if [ "${ARCH:-amd64}" != "amd64" ]; then
+        echo -e "\033[1;33mInstalling latest qemu emulators\033[0m"
+        docker pull -q ${QEMU_IMAGE};
+        docker run --rm --privileged ${QEMU_IMAGE} --uninstall qemu-*;
+        docker run --rm --privileged ${QEMU_IMAGE} --install all;
+      fi
   script:
     - ./scripts/lib/custom-docker-build
   rules: