Use kwarg ssl= instead of verify_ssl=  when init TCPConnector
Use kwarg ssl= instead of verify_ssl=  when init TCPConnector

Kwarg verify_ssl= has been deprecated and no longer takes any
effect on setting the property _ssl of a TCPConnector instance.
Use ssl= instead. For details see the following links.

https://github.com/aio-libs/aiohttp/blob/3.5/aiohttp/connector.py#L733
https://github.com/aio-libs/aiohttp/blob/3.5/aiohttp/client_reqrep.py#L152
https://github.com/aio-libs/aiohttp/blob/v0.18.4/aiohttp/connector.py#L402

CenterForOpenScience/waterbutler,felliott/waterbutler