Adjust read_timeout behavior for get_updates

[Bibo-Joshi]

When ready, closes #3893
Mostly as outlined in that issue. Also includes the suggestions from #3959

I decided to already change the default for read_timeout to DEFAULT_NONE, i.e. consider this a non-breaking change, because

• from reading the documentation of ApplicationBuilder.get_updates_read_timeout, Application.run_polling, Bot.get_updates, BaseRequest.do_request, it is not directly clear which value overrides which other value, such that IMO there is no completely clear expected behavior IMO
• in the stability policy have the clause "[…] changes of flavors of comparable behavior [are not covered]", which fits a change of the default timeout duration IMO.
• For custom implementations of BaseRequest nothing changes

ToDo:

• merge Improve write_timeout Handling for Media Methods #3952
• Added .. versionadded:: NEXT.VERSION, .. versionchanged:: NEXT.VERSION or .. deprecated:: NEXT.VERSION to the docstrings for user facing changes (for methods/class descriptions, arguments and attributes)
  • This is not done yet for the parameter read_timeout of Bot.get_updates - doing that after Improve write_timeout Handling for Media Methods #3952 is merged so that I don't have to change the logic of the insertion twice
• Created new or adapted existing unit tests
• Documented code changes according to the CSI standard <https://standards.mousepawmedia.com/en/stable/csi.html>__
• Added myself alphabetically to AUTHORS.rst (optional)
• [ ] Added new classes & modules to the docs and all suitable __all__ s
• Checked the Stability Policy <https://docs.python-telegram-bot.org/stability_policy.html>_ in case of deprecations or changes to documented behavior

[Poolitzer]

LGTM

[harshil21]

I had also gotten the same error as in #3893 while testing #3804 but I had dismissed it as an internet connection issue. Should've investigated further that time.

[harshil21]

lgtm :)