Automatically publish breaking-change log

[brson]

We should probably put this somewhere instead of making people look through git.

[steveklabnik]

We have [breaking-change] which helps with this, and http://bitrust.octarineparrot.com/ exists now as well. Given that we're following strong SemVer, will this be important enough to bother doing in the future?

[steveklabnik]

Two weeks later, I don't think so.