The tool is not used to validate its own changelog

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.

Inspect the repository's CI configuration and package scripts behind `yarn lint` and `yarn auto-changelog validate`. Trace which auto-changelog version each command invokes, then verify that lint performs changelog validation with the development version and that local formatting no longer conflicts with CI validation.

Written by the indexing model from the issue text.