The tool is not used to validate its own changelog

[mcmire]

Two issues:

• We run yarn auto-changelog validate in CI, but we do not run it as a part of yarn lint
• We are using the production version of auto-changelog to validate the changelog when we should be using the development version.

As a result, when saving the changelog locally, Prettier now adds new lines in between sections of the changelog, however, this causes the changelog to fail validation in CI.