Update puppetlabs-apt to latest version

These changes break backwards compatibility with older versions of
puppetlabs-apt.

Author: Patrick Robinson

.fixtures.yml

@@ -12,6 +12,6 @@ fixtures:
           repo: 'git://github.com/electrical/puppet-lib-file_concat.git'
         apt:
           repo: "git://github.com/puppetlabs/puppetlabs-apt"
-          ref: "1.8.0"
+          ref: "2.2.0"
     symlinks:
         puppet: "#{source_dir}"