Merge branch 'ruby3-sync-pipeline' into 'ruby3-sync'

Add a new ruby3 branch synchronization pipeline schedule

See merge request gitlab-org/gitlab!94121

.gitlab-ci.yml

+stages:
+  - sync
+  - notify
+
+default:
+  image:
+    name: alpine/git
+    entrypoint: ['']
+
+variables:
+  GIT_DEPTH: "20"
+  # 'GIT_STRATEGY: clone' optimizes the pack-objects cache hit ratio
+  GIT_STRATEGY: "clone"
+  GIT_SUBMODULE_STRATEGY: "none"
+  GET_SOURCES_ATTEMPTS: "3"
+
+.rules:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+    - when: manual
+      allow_failure: true
+
+gitlab:
+  stage: sync
+  extends: .rules
+  variables:
+    REPOSITORY: "https://dummy:${RUBY3_SYNC_TOKEN}@gitlab.com/gitlab-org/gitlab.git"
+    MERGE_FROM: "master"
+    MERGE_INTO: "ruby3"
+    USER_EMAIL: "project278964_bot10@noreply.gitlab.com"
+    USER_NAME: "project_278964_bot10"
+  environment:
+    name: ruby3-sync
+  before_script:
+    - git clone --filter=tree:0 "${REPOSITORY}" "${CI_JOB_NAME}"
+    - cd ${CI_JOB_NAME}
+    - git config user.email "${USER_EMAIL}"
+    - git config user.name "${USER_NAME}"
+    - git checkout "${MERGE_INTO}"
+    - git merge "origin/${MERGE_FROM}"
+  script:
+    - git push origin "${MERGE_INTO}"
+
+notify:
+  stage: notify
+  image: curlimages/curl
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "schedule"'
+      when: on_failure
+      allow_failure: true
+  variables:
+    NOTIFY_CHANNEL: f_ruby3
+  script:
+    - echo "NOTIFY_CHANNEL is ${NOTIFY_CHANNEL}"
+    - echo "CI_PIPELINE_URL is ${CI_PIPELINE_URL}"
+    - scripts/slack ${NOTIFY_CHANNEL} "☠️ synchronization for ruby3 failed! ☠️ See ${CI_PIPELINE_URL}" "x" "ruby3-sync"

README.md

+See https://gitlab.com/gitlab-org/gitlab/-/issues/340298#note_1041169793