Add PR notification to #oss-alerts

Author: jpr5

.github/workflows/notify-pr.yml

@@ -0,0 +1,25 @@
+name: PR Notification
+on:
+  pull_request_target:
+    types: [opened]
+jobs:
+  notify:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Notify Slack
+        if: github.actor != 'github-actions[bot]'
+        env:
+          SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
+          PR_TITLE: ${{ github.event.pull_request.title }}
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          PR_AUTHOR: ${{ github.event.pull_request.user.login }}
+          PR_NUM: ${{ github.event.pull_request.number }}
+          REPO_NAME: ${{ github.event.repository.name }}
+        run: |
+          if [ -z "$SLACK_WEBHOOK" ]; then echo "SLACK_WEBHOOK not set, skipping"; exit 0; fi
+          PAYLOAD=$(jq -n \
+            --arg text "New PR #${PR_NUM} on ${REPO_NAME} by *${PR_AUTHOR}*: <${PR_URL}|${PR_TITLE}>" \
+            '{text: $text}')
+          curl -sf -X POST "$SLACK_WEBHOOK" \
+            -H "Content-Type: application/json" \
+            -d "$PAYLOAD"