Missing changelog / upgrade guide

[enumag]

@jakubkulhan I can't find any changelog or upgrade guide for this repository. Except git history of course but I don't have time to study everything to see if there were any BC breaks. There are no release notes to look at either.

I'd like to use newer bunny in enqueue/amqp-bunny but when asked if bunny 0.3 or 0.4 have any BC breaks I have no way to answer that question.

[jakubkulhan]

There were no API changes. In version 0.3 react/promise was upgraded with fixes to its uses. In version 0.4 support for PHP < 7.0 was dropped.

[enumag]

Thanks. Still I want to suggest adding release notes to each tag with the new features and bugfixes.

[stevleibelt]

Indeed, a CHANGELOG.md would be very cool.
Also a note if this library is released using the Semantic Versioning would be great.

Linking to one of my projects, I am always writing the line "The current change log can be found here." in my README.md which is linked to the CHANGELOG.md.

The changelog is also good to have a central place (outside github) for upcoming features or known issues (at least that is how I am using it ;-)).