[9.0] (backport #282) New way of backporting to active branches using gh action

.github/workflows/backport-active.yml

@@ -0,0 +1,22 @@
+name: Backport to active branches
+
+on:
+  pull_request_target:
+    types: [closed]
+    branches:
+      - main
+
+permissions:
+  pull-requests: write
+  contents: read
+
+jobs:
+  backport:
+    # Only run if the PR was merged (not just closed) and has one of the backport labels
+    if: |
+      github.event.pull_request.merged == true && 
+      contains(toJSON(github.event.pull_request.labels.*.name), 'backport-active-')
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: elastic/oblt-actions/github/backport-active@v1

.mergify.yml

@@ -0,0 +1,123 @@
+commands_restrictions:
+  backport:
+    conditions:
+      - or:
+        - sender-permission>=write
+        - sender=github-actions[bot]
+defaults:
+  actions:
+    backport:
+      title: "[{{ destination_branch }}] (backport #{{ number }}) {{ title }}"
+      assignees:
+        - "{{ author }}"
+      labels:
+        - "backport"
+pull_request_rules:
+  - name: notify the backport policy
+    conditions:
+      - -label~=^backport
+      - base=main
+    actions:
+      comment:
+        message: |
+          This pull request does not have a backport label. Could you fix it @{{author}}? 🙏
+          To fixup this pull request, you need to add the backport labels for the needed
+          branches, such as:
+          * `backport-8./d` is the label to automatically backport to the `8./d` branch. `/d` is the digit.
+          * `backport-8.x` is the label to automatically backport to the `8.x` branch.
+          * If no backport is necessary, please add the `backport-skip` label
+
+  - name: remove backport-skip label
+    conditions:
+      - label~=^backport-\d
+    actions:
+      label:
+        remove:
+          - backport-skip
+
+  - name: notify the backport has not been merged yet
+    conditions:
+      - -merged
+      - -closed
+      - author=mergify[bot]
+      - "#check-success>0"
+      - schedule=Mon-Mon 06:00-10:00[Europe/Paris]
+    actions:
+      comment:
+        message: |
+          This pull request has not been merged yet. Could you please review and merge it @{{ assignee | join(', @') }}? 🙏
+
+  - name: backport patches to 8.x branch
+    conditions:
+      - merged
+      - base=main
+      - label=backport-8.x
+    actions:
+      backport:
+        assignees:
+          - "{{ author }}"
+        branches:
+          - "8.x"
+        labels:
+          - "backport"
+        title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"
+
+  - name: backport patches to 8.16 branch
+    conditions:
+      - merged
+      - base=main
+      - label=backport-8.16
+    actions:
+      backport:
+        assignees:
+          - "{{ author }}"
+        branches:
+          - "8.16"
+        labels:
+          - "backport"
+        title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"
+
+  - name: backport patches to 8.17 branch
+    conditions:
+      - merged
+      - base=main
+      - label=backport-8.17
+    actions:
+      backport:
+        assignees:
+          - "{{ author }}"
+        branches:
+          - "8.17"
+        labels:
+          - "backport"
+        title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"
+
+  - name: backport patches to 8.18 branch
+    conditions:
+      - merged
+      - base=main
+      - label=backport-8.18
+    actions:
+      backport:
+        assignees:
+          - "{{ author }}"
+        branches:
+          - "8.18"
+        labels:
+          - "backport"
+        title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"
+
+  - name: backport patches to 9.0 branch
+    conditions:
+      - merged
+      - base=main
+      - label=backport-9.0
+    actions:
+      backport:
+        assignees:
+          - "{{ author }}"
+        branches:
+          - "9.0"
+        labels:
+          - "backport"
+        title: "[{{ destination_branch }}] {{ title }} (backport #{{ number }})"