Please maintain a basic Changelog

[risicle]

It's one thing following semantic versioning (#160) but if you don't also maintain a Changelog file you're leaving developers to go and hunt for what's actually changed every time there's a major bump, and this process risks missing something (we got burnt by the exception handling changes which weren't mentioned anywhere outside the github issues). It doesn't have to include every change made - just the breaking ones. Putting these in a single, well-known place saves developers a lot of work.