chore: remove CI workflow before upstream PR

.github/workflows/pr_notify.yml

@@ -1,20 +0,0 @@
-name: PR Notifier
-
-on:
-  pull_request:
-    types: [opened, reopened, closed]
-
-jobs:
-  notify:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Notify Discord
-        env:
-          DISCORD_WEBHOOK_URL: ${{ secrets.DISCORD_WEBHOOK_URL }}
-        run: |
-          curl -H "Content-Type: application/json"           -d '{"content": "🔔 Pull Request [${{ github.event.pull_request.title }}](${{ github.event.pull_request.html_url }}) by ${{ github.event.pull_request.user.login }} - ${{ github.event.action }}"}'           $DISCORD_WEBHOOK_URL
-      - name: Notify Slack
-        env:
-          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
-        run: |
-          curl -H "Content-Type: application/json"           -d '{"text": ":bell: Pull Request <${{ github.event.pull_request.html_url }}|${{ github.event.pull_request.title }}> by ${{ github.event.pull_request.user.login }} - ${{ github.event.action }}"}'           $SLACK_WEBHOOK_URL