Python-engineio-client

* [chore] Bump engine.io-parser to version 2.0.1 (549)
* [chore] Bump concat-stream to version 1.5.2 (548)
* [feat] Allow to set the protocols for the websocket transport (546)

- [chore] Bump ws to version 1.1.2 (vulnerability fix) (539)
- [fix] Fix extraHeaders option in browser (536)

(bump following engine.io version)

- [chore] Fix Saucelabs tests (532)
- [chore] Actually run tests in Saucelabs (527)
- [feature] Allow extraHeaders to be set for browser clients in XHR requests (519)
- [feature] Add support for per transport options (518)
- [chore] Bump engine.io-parser to version 2.0.0 (525)
- [chore] Update zuul config to speed up tests (526)

(following engine.io bump)

- [chore] Bump engine.io-parser to version 1.3.2 (523)