Implement different version headers

[cburgdorf]

They differentiate between regular and patch versions:

https://github.com/ajoslin/conventional-changelog/blob/37f5561553c30d8f0f2c949502ea278da64949cd/lib/writer.js#L94-L96

[kbknapp]

After merging #27 this should be pretty easy to support using semver