Issue with listen gem version on Ruby 2.1.x

[richburroughs]

One of my co-workers ran into this today, using the latest version of the skeleton and I can duplicate it. When I run "bundle" with the included Gemfile on Ruby 2.1.7 I get:

Installing listen 3.1.4

Gem::InstallError: listen requires Ruby version >= 2.2.3, ~> 2.2.

Guard is pulling in listen as a dependency:

listen <= 4.0, >= 2.7

listen is at 3.1.4 but that's not compatible with Ruby 2.1.x. It looks like that changed with listen version 3.1.0.

I'm still kind of a Ruby noob and I'm not sure what the best way to handle this is. If I add listen to my Gemfile it works:

gem "listen", "~> 3.0.0"

Do we want to add that to the Gemfile? Or should users just use 2.2.x? I usually try to stick to the same Ruby that Puppet uses which is 2.1.x for me.

I can fix my module's Gemfile but it seems like other people will run into this.