Heroku CLI login now opens the browser by default
Change effective on 05 December 2018
By default, the heroku login command now opens your web browser to complete the login flow. To try it out, run heroku update to make sure you’re using the latest version of the CLI and then run heroku login.
Because of this change, Heroku Enterprise customers using SSO no longer need to include the --sso flag when logging in.
To continue using the interactive, terminal-based login flow, pass the --interactive option to heroku login. Enterprise SSO users also need to set the environment variable HEROKU_LEGACY_SSO=1.
To learn more, refer to the Dev Center.