Implement CHANGELOG

[chrisbloom7]

I got a dependabot upgrade PR to upgrade from 4.10 to 4.12. It would be helpful to be able to look at a changelog file to see what I should be on the look out for between minor version upgrades. Additionally, there is no 4.12 version tag so there's no way to compare from a previous version tag without looking at all the commits and finding the git sha for the 4.12 release. Could you commit to adding a changelog for future versions , and could you add a tag for 4.12 so future comparisons will be easier? (Both of these will also be used by dependabot to present changes between versions)

[adamzapasnik]

I agree, would be nice to have a changelog going forward @reidmorrison

[chrisbloom7]

@reidmorrison I see there are now tags for 4.12 and up. Thank you! I'd still love to see a CHANGELOG implemented