v0.2.1

Changed

• Releases are cut as GitHub Releases with the wheel and sdist attached,
  instead of being published to PyPI. Installs read the tag directly, so the
  tag is the distribution; the publish step needed a PyPI account that does
  not exist and failed on 0.2.0 without uploading anything. docs/RELEASING.md
  records what putting it on an index would take.
• The release workflow reads its notes from the matching CHANGELOG.md
  section and fails when there is none, rather than publishing an empty
  release. Its three jobs collapse into one — they existed to hand artifacts
  between runners for the upload that is now gone.

Fixed

• The install tag in README.md and docs/HOWTO.md is pinned to
  __version__ by a test. Both files carry it since installs come from git,
  and a release that bumped the version without touching them left a command
  that looks current but installs the previous server.