Creating a release

The release of the new version of Pyenv is done via GitHub Releases.

Release checklist:

Start drafting a new release on GitHub to generate a summary of changes. Save the summary locally.
- The summary may need editing. E.g. rephrase entries, delete/merge entries that are too minor or irrelevant to the users (e.g. typo fixes, CI)
Push the version number in libexec/pyenv---version
- Minor version is pushed if there are significant functional changes (not e.g. bugfixes/formula adaptations/supporting niche use cases).
- Major version is pushed if there are breaking changes
Update CHANGELOG.md with the new version number and the edited summary (only the changes section), reformatting it like the rest of the changelog sections
Commit the changes locally into master
Create a new tag with the new version number and push the changes including the tag
Create a new release on GitHub based on the tag, using the saved summary