Fixed a bug in which if you uses `-p` argument (to specify destination
part) _after_ choosing protocol (e.g. `-T` or `-X`), custom
destination port was ignored and we used default instead.

Display more context if a feature is not available due to missing dependency

Fixed a bug in which if you uses `-p` argument (to specify destination
part) _after_ choosing protocol (e.g. `-T` or `-X`), custom
destination port was ignored and we used default instead.

Display more context if a feature is not available due to missing dependency

- Add new dependencies
- Remove support for python 3.8
- Some other minor cleanups

also looking forward to bump minimum requirement to Python 3.10 so I can
get rid of all if-then-else clauses and use python 'match' statement.

…over-quic