Implementing parsers for Spam Complaints, Link Clicks and Subscription Change webhooks

[svandegar]

Hi!

I'm implementing these for myself and I thought I'd share with the community. Before I submit a PR, I just wanted to know if you'd be interested in these wrappers.

[Stranger6667]

Hi!

Sure! I'd be happy to review your PR! :) Could you, briefly describe what kind of problems these parsers solve?