Fix health check (#43)

Author: pcothenet

.github/workflows/health_check.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Notify slack
         uses: kpritam/slack-job-status-action@v1
         with:
-          if: ${{ failure() }}
+          if: failure()
           job-status: ${{ job.status }}
           slack-bot-token: ${{ secrets.SLACK_BOT_TOKEN }}
           channel: eng-notifications