Bored to write app name in every heroku command though I got only 1 app

If you have the heroku-accounts plugin installed, switching to the heroku branch worked for me, as discussed in this answer.

To swap out your existing version of the heroku-accounts plugin, use:

heroku plugins:install https://github.com/heroku/heroku-accounts.git

Note that if you've followed @Moemars answer, you'll need to switch your git remote back to https.

Going to post this just in case it helps someone else out. I had the same problem even though there was only one app installed. I had to switch my heroku remote url from https to git.

https://git.heroku.com/[heroku-app-1234].git

to

[email protected]:[heroku-app-1234].git

Then everything worked normally for myself.

git remote remove heroku
git remote add heroku [email protected]:[heroku-app-1234].git

If heroku is claiming that there are multiple apps in the folder you must have more than one remote in your .git/config.

Remove the extra heroku remote or set the default using git config heroku.remote remote_name