Log Message:
Update to 0.19.0. From the changelog:

* implement --nocache option
* new plugin: ikiwiki toot
* fix incorrect string stripping in README (Closes: GL#29)
* cleanups:
  * add support for Python 3.10, no change
  * remove the test compatibility shim from setup.py
  * silence warnings from lxml missing type hints
  * more uniform variable naming (underscores)