Snap version reports being out of date

[fcole90]

Hi, I'm using the snap of travis. However it reports being out of date. This happens in both the stable (1.8.9) and edge (1.8.13) channels.

$ travis
Outdated CLI version, run `gem install travis`.
...

I think there are two issues in one:

1. the package should either be updated more often or, if this is an intended pace of release, it should not show any warning of this kind
2. it should not suggest updating it using gem install when it is installed as a snap

Do you want me to split the second out in a separate issue?

[fcole90]

I'm checking the feasibility for a patch to have the snap and the gem in sync, using the version of the Gemfile to get the correct version.

Discussion: https://forum.snapcraft.io/t/get-version-from-gemfile-and-use-it-in-source-field