fix: remove manual installation of buildx

.gitlab-ci.yml

@@ -96,12 +96,13 @@ build:
     - "$DOCKER_DIND_IMAGE"
   image: "$DOCKER_DIND_IMAGE"
   before_script:
-    # Install buildx
-    - mkdir -p ~/.docker/cli-plugins
-    - wget "https://github.com/docker/buildx/releases/download/v$BUILDX_VERSION/buildx-v$BUILDX_VERSION.linux-amd64" -O ~/.docker/cli-plugins/docker-buildx
-    - chmod a+x ~/.docker/cli-plugins/docker-buildx
-    # See https://www.docker.com/blog/multi-platform-docker-builds/
-    - docker run --rm --privileged docker/binfmt:a7996909642ee92942dcd6cff44b9b95f08dad64
+    # See https://docs.docker.com/build/building/multi-platform/#qemu
+    # To be able to build for arm64 which is not native to hosted runners,
+    # we need to inject a stub for being able to do so.
+    #
+    # The container below is used by the docs article above and hence
+    # considered upstream, even though it's in a non-Docker namespace.
+    - docker run --rm --privileged tonistiigi/binfmt
     # Registry auth
     - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" "$CI_REGISTRY"
   script: