aiohttp.ClientSession read_timeout is deprecated

[chuckwondo]

When using pfun.http (pfun 0.13.1), I get the following deprecation warning:

.../pfun/http.py:104: DeprecationWarning: read_timeout is deprecated, use timeout argument instead

[chuckwondo]

It looks like you should simply change the default value of read_timeout to aiohttp.client.sentinel (like you do for timeout) instead of None.

[chuckwondo]

As a means to silence the deprecation warning, we can do this, for example:

import aiohttp
from pfun.http import HTTP

class Env:
    http = HTTP(read_timeout=aiohttp.helpers.sentinel)

Notice also that sentinel appears to have moved from aiohttp.client to aiohttp.helpers, or perhaps it has always been there, but using aiohttp.client.sentinel causes pyright to produce the error message "sentinel" is not exported from module "aiohttp.client", whereas using aiohttp.helpers.sentinel does not.

[chuckwondo]

I see that both read_timeout and conn_timeout were deprecated in aiohttp 3.5.0 (2018-12-22), so perhaps these should be removed from the pfun.http.HTTP constructor altogether (or at least deprecated in pfun as well).