add the packaging metadata to build the travis snap

[come-maiz]

This package will let you publish the latest travis CLI in the Ubuntu store, and from there reach many users on all the supported Ubuntu versions, and more Linux distributions.

[come-maiz]

You can read more about snaps in https://snapcraft.io

To test this in an Ubuntu 16.04 machine:

$ sudo apt install git snapcraft
$ git clone https://github.com/elopio/travis.rb
$ cd travis.rb
$ git checkout snapcraft
$ snapcraft
$ sudo snap install *.snap --dangerous

(dangerous because the snap you build is not signed from the store. Your users will just have to run sudo snap install travis once you push it in the store)

If you have any questions, please let me know.

[guilhem]

any news? 👼