bump nats-py to >=2.2.0

Fixes for nats-py v2 support

Update nats-py v2.1.0 from 2.0.0

Fix NATS.request usage

Bugfix

nats-py v2, Python 3.10

Improve documentation. See https://nats-request-asap.readthedocs.io

Set long description format to markdown

Document exceptions raised.

Refactor code to be simpler.

A working version of the `request` function. It returns one or multiple

Msg responses to a NATS request as soon as possible.