Log Message:
feed2exec: update to 0.20.0. Changes:

* Add matchtitleregex and droptitleregex plugin and tests
* implement codespell linting, fixing all found errors
* more related software: rss-bridge
* isort: sort imports all over
* add missing readthedocs configuration file, now mandatory
* cross-reference droptitle and droptitle-regex

pkgsrc changes:

- Convert to wheel.mk
- Avoid self-conflicts when installing under multiple pythons