meta: notify slack when someone force pushes

Notify #nodejs-dev on the OpenJS Foundation slack when someone
force-pushes, removing one manual step from force-pushing.

PR-URL: #35131
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: mmarchini

.github/workflows/notify-force-push.yml

@@ -0,0 +1,25 @@
+on:
+  push:
+    branches:
+      - master
+
+name: Notify on Force Push
+jobs:
+  slackNotification:
+    name: Slack Notification
+    if: ${{ github.event.forced && github.repository == 'nodejs/node' }}
+    runs-on: ubuntu-latest
+    steps:
+    - name: Slack Notification
+      uses: rtCamp/action-slack-notify@master
+      env:
+        SLACK_COLOR: '#DE512A'
+        SLACK_ICON: https://github.com/nodejs.png?size=48
+        SLACK_TITLE: '${{ github.actor }} force-pushed to ${{ github.ref }}'
+        SLACK_MESSAGE: |
+          A commit was force-pushed to <https://github.com/${{ github.repository }}/tree/master|${{ github.repository }}@master> by <https://github.com/${{ github.actor }}|${{ github.actor }}>
+
+          Before: <https://github.com/${{ github.repository }}/commit/${{ github.event.before }}|${{ github.event.before }}>
+          After: <https://github.com/${{ github.repository }}/commit/${{ github.event.after }}|${{ github.event.after }}>
+        SLACK_USERNAME: nodejs-bot
+        SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}