[WIP] First pass at GHA to automate changelog generation for release

[emmyoop]

resolves #4789

Description

This is a WIP and not complete but want to document where I stopped even though the release process is currently being reworked.

Inputs:

• version (ex: 1.1.0)
• is prerelease (true/false)
• prerelease (ex: rc2)

Uses the changie docker container to run the batch and merge commands from given input. There are two options:

1. Generate a CHANGELOG for a pre-release
   • creates a markdown file from yaml files in the /unreleased directory and moves all those yaml files into a directory named for the input version. The markdown file will be named in the format of <version>-<prerelease>.md ie. 1.1.0-b1.md
   • creates the new CHANGELOG.md file by combining all .md files in the /.changes directory. There can be multiple pre-releases for a single release.
2. Generate a CHANGELOG for a final release
   • creates a markdown file from all the yaml files in the /unreleased directory and the /<version> directory. Deletes all yaml files in those directories. Also deletes all markdown files for the prerelease of this version. (ie, 1.1.0-b1.md, 1.1.0-rc1.md...) since those changes are collapsed down and included in the new markdown file.
   • creates the new CHANGELOG.md file for the version. This collapses all pre-release versions into a single release.

Checklist

• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have added information about my change to be included in the CHANGELOG.

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the contributing guide.

[emmyoop]

This is already part of version_bump.yml!