New minor version releases should combine release notes from all pre-release versions

The post-release workflow only takes a single previous version. For new minor GA releases, we need to combine release notes from all pre-release versions for the minor.

Start by locating the post-release workflow and reading how it selects the previous version and release notes. Trace the path used for a new minor GA release, then determine how all pre-release versions for that minor are collected and combined. Done means the workflow includes release notes from every relevant pre-release version.

Written by the indexing model from the issue text.