build: add slack-notificaitons

Author: manchuck

.github/workflows/release.yml

@@ -0,0 +1,39 @@
+name: Release Action
+
+on:
+  release:
+    types:
+      - published
+
+jobs:
+  notify-release:
+    runs-on: ubuntu-latest
+    name: Notify Release
+    strategy:
+      matrix:
+        url: [SLACK_WEBHOOK_ASK_DEVREL_URL, SLACK_WEBHOOK_DEVREL_TOOLING_URL, SLACK_WEBHOOK_DEVREL_PRIVATE_URL, SLACK_WEBHOOK_COMMUNITY]
+    steps:
+      - name: Send to slack channels
+        uses: slackapi/slack-github-action@v2.0.0
+        with:
+          webhook: ${{ secrets[matrix.url]}}
+          webhook-type: incoming-webhook
+          errors: true
+          payload: |
+            blocks:
+              - type: "header"
+                text:
+                  type: "plain_text"
+                  text: ":initial_external_notification_sent: :python: Version ${{ github.event.release.name }} of the Python SDK has been released"
+              - type: "section"
+                text:
+                  type: "mrkdwn"
+                  text: "${{ github.event.release.body }}"
+              - type: "divider"
+              - type: "section"
+                text:
+                  type: "mrkdwn"
+                  text: "You can view the full change log <${{github.event.release.html_url }}|here>"
+
+
+