Removed the need for config.json when releasing
Removed the need for config.json when releasing

no issue

- we previously needed a config.json to provide the GitHub token for
  publishing new Casper releases
- this commit removes the need for this file by pulling the token from
  the environment variable, which everyone in the Core team has set up

eduardochiaro/Casper-Light,dlew/Casper,eduardochiaro/Casper-Light,TryGhost/Casper,ImKcat/ImKcatCasper