Improve package name regex

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

ee/lib/ee/gitlab/regex.rb

@@ -14,7 +14,7 @@ module EE
       end
 
       def package_name_regex
-        @package_name_regex ||= %r{\A(([\w\-\.\@]*)/)*([\w\-\.]*)\z}.freeze
+        @package_name_regex ||= %r{\A\@?(([\w\-\.]*)/)*([\w\-\.]*)\z}.freeze
       end
 
       def maven_path_regex

ee/spec/lib/gitlab/regex_spec.rb

@@ -27,7 +27,9 @@ describe Gitlab::Regex do
     it { is_expected.to match('foo') }
     it { is_expected.to match('foo/bar') }
     it { is_expected.to match('@foo/bar') }
+    it { is_expected.to match('com/mycompany/app/my-app') }
     it { is_expected.not_to match('$foo/bar') }
+    it { is_expected.not_to match('@foo/@/bar') }
     it { is_expected.not_to match('my package name') }
     it { is_expected.not_to match('!!()()') }
   end