Bump version to 1.18.1

Merge pull request aws#949 from aws/dev

Merge dev into master

Bump version to 1.16.0

Bump version to v1.15.1

cr https://code.amazon.com/reviews/CR-10577762

Bump version to v1.15.0

Bump version to 1.14.1

Bump version to 1.14.0

Bump version to 1.13.1

Bump version to 1.13.0

Bump version to 1.12.1