Declare support for Python 3.8

[hugovk]

No description provided.

[pradyunsg]

Thanks for filing this @hugovk!

Could you:

• update docs/html/installing.rst:112 for Python 3.8?

• add news/7219.feature with the following content?

  Document Python 3.8 support.
  

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We'd also want to add it to CI as well (in a follow up PR).

[hugovk]

Updated!

About adding it to CI:

• The Travis CI config is already testing 3.8-dev, currently Python 3.8.0rc1+, pretty much the same thing as 3.8.0 final. That could be moved further up, but I expect Travis will add 3.8.0 soon.

  • Tracking issue: https://travis-ci.community/t/add-python-3-8-support/5463

• AppVeyor are adding it in their next images update: Python 3.8.0 appveyor/ci#3142

• Azure Pipelines: I've not checked it yet

[hugovk]

• Azure Pipelines: I've not checked it yet

Tracking issue: https://github.com/microsoft/azure-pipelines-image-generation/issues/1317

[chrahunt]

@hugovk, can you please file an issue that we can use as a checklist for 3.8 CI updates? Essentially containing the info from your comment above and linking to the tracking issues and our own PR(s).

[hugovk]

Sure, please see issue #7229.

[chrahunt]

Perfect, thank you!

[pradyunsg]

Awesome stuff! Thank you so much @hugovk!

Thanks for reviewing and merging this @chrahunt!

[pradyunsg]

@xavfernandez this is an RM decision but I forgot to flag it to you before the release -- 3.8.0 release was basically in sync with pip 19.3, and I think we should have a pip release (19.3.1?) that has support for it explicitly declared.

[xavfernandez]

Without a bugfix, I don't think I would have bothered but #6606 is a good reason :)