Confirmation for ml upgrade command doesn't recognize 'yes' as affirmative

[peterskim12]

ml upgrade command asks the user if he/she wants to continue. It only seems to accept 'y' to express an affirmative response. It should also accept 'yes' and probably also any variations of capitalization. e.g. 'Yes', 'YES", etc.

Peters-MacBook-Pro:rlus_demo pkim$ ./ml upgrade --branch=dev
This command will attempt to upgrade to the latest Roxy files.
Before running this command, you should have checked all your code
into a source code repository, such as Git or Subversion. Doing so
will make it much easier to fix problems if something goes wrong.

Are you ready to proceed?
yes
later