リモートブランチ名まちがいたしw
$ git push heroku remove-extra-libidn:heroku
Enumerating objects: 137960, done.
Counting objects: 100% (137960/137960), done.
Delta compression using up to 8 threads
Compressing objects: 100% (34924/34924), done.
Writing objects: 100% (137960/137960), 153.17 MiB | 537.00 KiB/s, done.
Total 137960 (delta 102711), reused 136099 (delta 101012), pack-reused 0
remote: Pushed to branch other than [main, master], skipping build.
* [new branch] remove-extra-libidn -> heroku