chore: add test slack workflow

Author: marcomontalbano

.github/workflows/test-slack.yaml

@@ -0,0 +1,60 @@
+name: Test Slack Notification
+
+on:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Post to a Slack channel
+        id: slack
+        uses: slackapi/slack-github-action@v3.0.1
+        with:
+          webhook: ${{ secrets.PIPELINE_SLACK_CHANNEL_WEBHOOK_URL }}
+          webhook-type: incoming-webhook
+          # Slack channel id, channel name, or user id to post message.
+          # See also: https://api.slack.com/methods/chat.postMessage#channels
+          # channel-id: 'pipeline'
+          # For posting a rich message using Block Kit
+          payload: |
+            {
+              "text": "Testing Slack Notification ${{github.ref_name}} for ${{github.event.repository.name}}.",
+              "blocks": [
+                {
+                  "type": "section",
+                  "text": {
+                    "type": "mrkdwn",
+                    "text": "Testing Slack Notification for <${{github.event.repository.html_url}}|`${{github.event.repository.name}}`>\n*<${{github.event.release.html_url}}|release notes>*"
+                  }
+                },
+                {
+                  "type": "section",
+                  "fields": [
+                    {
+                      "type": "mrkdwn",
+                      "text": "*Project:*\n${{github.event.repository.name}}"
+                    },
+                    {
+                      "type": "mrkdwn",
+                      "text": "*Version:*\n${{github.ref_name}}"
+                    }
+                  ]
+                },
+                {
+                  "type": "context",
+                  "elements": [
+                    {
+                      "type": "image",
+                      "image_url": "${{github.event.sender.avatar_url}}",
+                      "alt_text": "${{github.event.sender.login}}"
+                    },
+                    {
+                      "type": "mrkdwn",
+                      "text": "*${{github.event.sender.login}}* has triggered this release."
+                    }
+                  ]
+                }
+              ]
+            }