ci: build image on master

.gitlab-ci.yml

+default:
+  image: ${CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX}/node:14.19.3-alpine
+  services:
+    - name: ${CI_DEPENDENCY_PROXY_DIRECT_GROUP_IMAGE_PREFIX}/docker:20.10.9-dind
+      alias: docker
+  tags:
+    - build-push-to-registry
+
+stages:
+  - build
+
+build-job:
+  stage: build
+  only:
+    - master
+  script:
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build --pull -t "$CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG" .
+    - docker push "$CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG"
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