Replace use of deprecated socket.timeout and socket.error errors

[michaeloliverx]

I noticed that we are using socket.error and socket.timeout in a few places e.g.

httpcore/httpcore/backends/sync.py

Line 23 in 18ba03a

exc_map = {socket.timeout: ReadTimeout, socket.error: ReadError}

According to the docs they are now aliased to OSError and TimeoutError respectively.

Should we replace all references of these?

[tomchristie]

On first sight that looks like a sensible change to me.

But... I'm not sure that works prior to Python 3.10.

I think for Python 3.9 and lower we still need to use socket.timeout...

$ python 
Python 3.9.7 (v3.9.7:1016ef3790, Aug 30 2021, 16:39:15) 
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import socket
>>> socket.timeout
<class 'socket.timeout'>
>>> socket.timeout.__mro__
(<class 'socket.timeout'>, <class 'OSError'>, <class 'Exception'>, <class 'BaseException'>, <class 'object'>)

[tomchristie]

Closed via #609.