Remove GH token from Travis file

[lmazuel]

We don't want to push this token to private when syncing

@salameer @veronicagg @marstr

[veronicagg]

I'm ok with the change, I see that you added the token in Travis settings already. How does the env var token get consumed?

[lmazuel]

@veronicagg Travis allows two way to passe secure env variables:

• global.secure section in Travis.yaml
• Env variables in settings

This is the same thing, so removing the global.secure section means that now Travis will search for GH_TOKEN in the settings (and it will find it). So no change at all of behavior, we just move the token from one spot to another.

From the doc:

If you define a variable with the same name in .travis.yml and in the Repository Settings, the one in .travis.yml takes precedence.

https://docs.travis-ci.com/user/environment-variables/#Defining-encrypted-variables-in-.travis.yml
https://docs.travis-ci.com/user/environment-variables/#Defining-Variables-in-Repository-Settings