changelog: Add auto-changelog action step to gh-actions

[elycruz]

We should add this to automatically populate our change log file.

Acceptance Criteria

Add gh-action step for updating our existing CHANGELOG.md file to contain release notes between previously published tag and latest published tag.

See example/potential-candidate gh-action here:
https://github.com/requarks/changelog-action

[elycruz]

No longer required - Detailed Change log is kept by github (via tags and releases logs).