Fix method_missing for ActiveCampaign module

[tdtadeu]

Fixes #16 by defining method_missing as a class method, so it's called when running methods on the module directly, such as ::ActiveCampaign.list_list(ids: "all").

[tdtadeu]

I was able to fix rubocop config file, but now it returns 13 offenses. I'll see if I can help fixing them later

[mhenrixon]

Awesome! Thanks, it is probably time to do some upgrades in the gem.

[tdtadeu]

Got 10 of them, but the 3 remaining seem to be related to the complexity of :== method in the configuration. My first idea was to simply remove it completely, but maybe I'm missing where this method is needed?

[tdtadeu]

I'm in a bit of a hurry to get things working for my company, but as soon as things cool down I'll look into upgrading the dependencies. I just need a bit of help with the == method in lib/active_campaign/configuration.rb. If it's needed, maybe we should disable complexity checks for the configuration? It's not even that complex 🤓