Handle pickle in BaseUrlSession for base_url

[Inokinoki]

• Add base_url when __getstate__ is called
• Try to take base_url when __setstate__ is called

Resolve #375

[sigmavirus24]

Can you add something to the change log too?

[Inokinoki]

Can you add something to the change log too?

Should I put in 1.0.0 section?

[sigmavirus24]

Nope. Create a 1.1.0 section. 1.0 was already released

[sigmavirus24]

Can you look into the test failures? I don't see them in main

[Inokinoki]

Can you look into the test failures? I don't see them in main

Done, but it's quite weird that two of the content length of the recorded data are wrong:

For example, httpbin:

'{\n  "args": {}, \n  "headers": {\n    "Accept": "*/*", \n    "Accept-Encoding": "gzip, deflate", \n    "Host": "httpbin.org", \n    "User-Agent": "python-requests/2.8.1"\n  }, \n  "origin": "<IPADDR>", \n  "url": "https://httpbin.org/get"\n}\n'
>>> len(_)
233

[sigmavirus24]

Things failing on 3.12 are failing on a deprecation warning that needs to be fixed elsewhere.

Thanks for working through this!