Release 0.15.0 preparation

[chalin]

Issues/PRs in scope

• Update [official-support] link in README.md - Set version to 0.14.2-dev-001-over-main-20ff86e7, and more #2542
• See 0.15.0 milestone
• ...

Fixed issues: Resolved 0.15.0 issues.

Release-prep checklist

For the complete instruction set, see Publishing a release:

• Update Changelog: for inspiration, go over changes since last release v0.14.0...main
• Update the Docsy version in package.json and docsy.dev/hugo.yaml
• Test pre-release from branch
• Pre-release patches?
• Create and push new version tag
• Create and publish the new release 🎉

Docsy example followup (tracked separately):

• https://github.com/google/docsy-example/pull/xxx

Other / related

• v0.14.0...main
• Release 0.14.0 and 0.14.1 preparation #2404
• List of most-upvoted issues