Update changelog, prep for 1.4.3

Update changelog, prep for 1.4.2

Prep for version 1.4.1

Mention HighWaterMarkOffset method in changelog

Prep for version 1.3.0

Prepare for version 1.2.0

Hopeful quick fix for flaky CI

Merge pull request IBM#361 from Shopify/readme-semantic

Update README for semantic versioning and gopkg.in