Updates apt::source usage

The use of key_source in apt::source is deprecated since puppetlabs/apt
version 2.1.1 (at least) and removed in version 4.0.0.

Author: amateo

manifests/repos.pp

@@ -21,8 +21,10 @@
           location          => $location,
           release           => $docker::package_release,
           repos             => $docker::package_repos,
-          key               => $package_key,
-          key_source        => $key_source,
+          key               => {
+            id     => $package_key,
+            source => $key_source,
+          },
           required_packages => 'debian-keyring debian-archive-keyring',
           include_src       => false,
         }

metadata.json

@@ -9,7 +9,7 @@
   "issues_url": "https://github.com/garethr/garethr-docker/issues",
   "dependencies": [
     {"name":"puppetlabs/stdlib","version_requirement":">= 4.1.0"},
-    {"name":"puppetlabs/apt","version_requirement":">= 1.8.0 <= 3.0.0"},
+    {"name":"puppetlabs/apt","version_requirement":">= 2.1.0"},
     {"name":"stahnma/epel","version_requirement":">= 0.0.6"}
   ],
   "data_provider": null,