expose `jwt` for token based logon, if set will override u/p.

gh actions

add instrument_type to exchange subscription. updated pydoc links

updated

remove noise

Read symbol from SubscriptionResponse message. Fixes no callbacks for…

… subscriptions like: ES*0, ESM21, etc.

fixed doc links

updated to latest protos.

* added `request_available_exchanges`
* exposed `service` and `subscription_type`

back to pep517 for now.

Update README.md