Twitter API version 1.0 is deprecated

During the chatterbot-register execution, there is an attempt to get bot's username. This GET is using a deprecated version of Twitter API (according to https://dev.twitter.com/docs/api/1/get/account/verify_credentials) and returns an error message.

Twitter API version 1.1 (https://dev.twitter.com/docs/api/1.1/get/account/verify_credentials) should be used instead.