Changelog watcher

[Oleg A.]

Now anyone can make PR and forget to add changelog file...

How about add something like this to check CHANGES folder and automatically ask author to add file with changes description?

[Sam Bull]

For these smaller repos, I kind of prefer to just look through the commits and write up the changelog manually. For something like aiohttp, it would be unmanageable, and towncrier certainly makes a lot of sense there.