Bump slack-github-action to v2.2.1 in Tests workflow

Author: ppawlowski

.github/workflows/tests.yml

@@ -230,7 +230,7 @@ jobs:
         fi
 
     - name: Send notification
-      uses: slackapi/slack-github-action@485a9d42d3a73031f12ec201c457e2162c45d02d # v2.0.0
+      uses: slackapi/slack-github-action@91efab103c0de0a537f72a35f6b8cda0ee76bf0a # v2.1.1
       with:
         method: chat.postMessage
         token: ${{ secrets.SLACK_GHBOT_TOKEN }}