Pessimistically lock deps to `MAJOR.MINOR`
Update to `git` cookbook `~> 3.0`
Switch to using the `yum-epel` cookbook

The main `yum` cookbook was recently refactored into a number of
repo-specific cookbooks. Previously we relied on the `yum::epel` but now
should use the `yum-epel::default` recipe.
Merge branch 'schisamo/update-deps'