Mutt-ical

Minor tweaks to the package metadata. Version number bump solely to
facilitate PyPI publishing.

Just minor documentation tweaks, plus a bump to the version number for
publishing to PyPI.

I wasn't doing versioned releases until 2.0.0, but a summary of changes
between the original 1.0.0 release and 2.0 includes:

Added

- Show recurrence rules in an event
- Added display of URL and Comment iCalendar fields
- Set up packaging with Poetry
- Released on PyPI