Log Message:
py-textile: updated to 4.0.3

Version 4.0.3
* Update supported Python versions to 3.8 - 3.12
* Replace html5lib with nh3 for html sanitization
* General code cleanup
* Bugfixes:
**  Wrong HTML output when "bc.." is the very last in the document
* Other:
** Use github actions instead of travis for automated testing