feat(ci): notify on release (#53)

Author: matoous

.github/workflows/notification.yaml

@@ -0,0 +1,21 @@
+on:
+  release:
+    types: [published]
+
+permissions:
+  contents: read
+
+jobs:
+  notify:
+    name: Notify
+    runs-on: ubuntu-latest
+    steps:
+      - name: Send release notification
+        uses: slackapi/slack-github-action@485a9d42d3a73031f12ec201c457e2162c45d02d # v2.0.0
+        with:
+          webhook: ${{ secrets.SLACK_WEBHOOK_URL }}
+          webhook-type: webhook-trigger
+          payload: |
+            repo: "${{ github.repository }}"
+            url: "${{ github.event.release.html_url }}"
+            version: "${{ github.event.release.tag_name }}"