You’re probably using an old version or the deprecated package 'heroku-cli'. The new one is just called ‘heroku’
Uninstall that by
npm uninstall -g heroku-cli
Then install the new package
npm i -g heroku
And now all your works will go perfectly.Just try heroku login and any other heroku command.
Credit: https://github.com/heroku/cli/issues/855#issuecomment-394758388