chore: update slack alerts color (twilio#179)

Author: shwetha-manvinkurke

.github/workflows/cli-core-test.yml

@@ -41,7 +41,7 @@ jobs:
         uses: rtCamp/action-slack-notify@v2
         env:
           SLACK_WEBHOOK: ${{ secrets.ALERT_SLACK_WEB_HOOK }}
-          SLACK_COLOR: ${{ job.status }}
+          SLACK_COLOR: 'danger'
           SLACK_USERNAME: CLI Github Actions
           SLACK_MSG_AUTHOR: twilio-dx
           SLACK_ICON_EMOJI: ':github:'