Fix @channel mention in create-release

Author: vjern

.github/workflows/create-release.yml

@@ -59,15 +59,12 @@ jobs:
         id: slack
         uses: slackapi/slack-github-action@v1.24.0
         with:
-          # Slack channel id, channel name, or user id to post message.
-          # See also: https://api.slack.com/methods/chat.postMessage#channels
           channel-id: ${{ secrets.SLACK_CHANNEL_ID }}
           slack-message: |
-            <@channel> New release ${{ env.VERSION_NAME }} has been triggered by ${{ github.actor }} :rocket:
-          # For posting a rich message using Block Kit
+            <!channel> New release ${{ env.VERSION_NAME }} has been triggered by ${{ github.actor }} :rocket:
         env:
           SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
-    
+
       - name: Trigger release process in giskard-hub
         uses: peter-evans/repository-dispatch@v2
         with: