Add contributor to the CHANGELOG.md

Get release 3.1.2 ready.

Prepare for release 3.1.1

Merge pull request IBAnimatable#361 from IBAnimatable/hotfix/swiftlint

Bump swiftlint 0.13.0

Merge pull request IBAnimatable#353 from IBAnimatable/feature/get-rel…

…ease-3.0.1-ready

Get release 3.0.1 ready.

Merge pull request IBAnimatable#352 from IBAnimatable/feature/get-rel…

…ease-2.8.2-ready

Get release 2.8.2 ready.

Update README.md to describe version 3.

Get Release 2.8.1 ready.

Get Release 2.8 ready.

Merge pull request IBAnimatable#296 from IBAnimatable/feature/get-2-7…

…-ready

Get release 2.7 ready