Add initial support py3.9

[jaimcamp]

Changes proposed in this pull request:

• Adds support for python 3.9 in the tox environment, github actions, setuptools and Travis.

[codecov-io]

Codecov Report

Merging #171 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #171   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
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  Files            9         9           
  Lines          569       569           
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  Hits           569       569           

Flag	Coverage Δ
#GHA_Ubuntu	100.00% <ø> (ø)
#GHA_Windows	100.00% <ø> (ø)
#GHA_macOS	100.00% <ø> (ø)

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[hugovk]

Thanks!

We're still waiting for 3.9 on Travis CI (https://travis-ci.community/t/python-3-9-0-build/10091?u=hugovk) so please can you leave it on 3.9-dev for now? We can update that later when it's available.

The PyPy3 / Windows failure looks unrelated, also occurs on master and already reported at actions/setup-python#151, so let's not worry about that here.

[jaimcamp]

Thanks!

We're still waiting for 3.9 on Travis CI (https://travis-ci.community/t/python-3-9-0-build/10091?u=hugovk) so please can you leave it on 3.9-dev for now? We can update that later when it's available.

The PyPy3 / Windows failure looks unrelated, also occurs on master and already reported at actions/setup-python#151, so let's not worry about that here.

Got it, pushed a commit to roll-back the support in travis, can be easily revered in the future 👍

[hugovk]

Thank you!