fix review app determination logic

Author: Dottenpixel

.github/actions/set-heroku-app-name/action.yml

@@ -27,7 +27,7 @@ runs:
     # All other cases publish to the review app
     run: |-
       echo 'HEROKU_RELEASE_STORYBOOK_APP_NAME=false' >> $GITHUB_OUTPUT
-      if [[ "${{ github.event.ref_name }}" = "${{ github.event.repository.default_branch }}" ]] ; then
+      if [[ "${{ github.ref_name }}" = "${{ github.event.repository.default_branch }}" ]] ; then
         echo "Publishing to UPCOMING..."
         echo 'HEROKU_APP_NAME=${HEROKU_APP_UPCOMING}' >> $GITHUB_OUTPUT
         echo 'HEROKU_RELEASE_STORYBOOK_APP_NAME=storybook-upcoming' >> $GITHUB_OUTPUT