chore(release): change env variable to set github origin

Author: christianalfoni

.travis.yml

@@ -29,7 +29,7 @@ script:
 after_success:
   - |
     if [[ $TRAVIS_SECURE_ENV_VARS == 'true' ]]; then
-      git remote set-url origin https://cerebraljs:${GH_TOKEN}@github.com/cerebral/overmind;
+      git remote set-url origin https://cerebraljs:${REPO_COOKER_GITHUB_TOKEN}@github.com/cerebral/overmind;
       git config --global user.email "[email protected]";
       git config --global user.name "Cerebral JS";
     fi