Update auto_update_preview.yml

Attempt to fix notification trigger

Author: gricher-crto

.github/workflows/auto_update_preview.yml

@@ -55,7 +55,7 @@ jobs:
           GH_TOKEN: ${{ github.token }}
 
       - name: Send notification
-        if: ${{ failure() }} || steps.check_changes.outputs.has_changes == 'true'
+        if: ${{ failure() || steps.check_changes.outputs.has_changes == 'true' }}
         uses: rtCamp/action-slack-notify@v2
         env:
           SLACK_CHANNEL: criteo-api-sdk-generator