Add python 3.9-dev support

[pdecat]

Replace python version 3.8-dev by 3.8 and add 3.9-dev.

We may want to drop 3.4 and maybe even 2.7 at some point, but there's no real gain right now. Maybe later if a cleanup or refactoring is considered at some point.

See https://devguide.python.org/#status-of-python-branches for officially supported python branches.

[pdecat]

Travis CI job: https://travis-ci.org/github/venth/aws-adfs/builds/703765067

Like I said in #164 (review), I'm not sure why the Travis build results do not show up in PRs. Probably some settings to adjust.

Alternatively, we switch to Github Actions to get a more streamlined experience.

[pdecat]

Some tests are failing with python 3.9-dev: https://travis-ci.org/github/venth/aws-adfs/jobs/703765074

test/test_account_aliases_fetcher.py .......                             [ 23%]
test/test_assertion_extractor.py ..FFF                                   [ 40%]
test/test_authenticator.py .....                                         [ 56%]
test/test_click_parses_command_line_arguments.py .                       [ 60%]
test/test_config_preparation.py ..                                       [ 66%]
test/test_fetch_html_encoded_roles.py ..                                 [ 73%]
test/test_role_chooser.py .......                                        [ 96%]
test/test_version.py .                                                   [100%]

The underlying error is the same for all three failing tests:

>           encoded_assertion = base64.encodestring(assertion.encode('utf-8')).decode('utf-8')
E           AttributeError: module 'base64' has no attribute 'encodestring'

[pdecat]

From https://docs.python.org/3.9/whatsnew/3.9.html#removed:

base64.encodestring() and base64.decodestring(), aliases deprecated since Python 3.1, have been removed: use base64.encodebytes() and base64.decodebytes() instead.

Note: simply replacing base64.encodestring() calls to base64.encodebytes() would mean dropping support for python 2.7 (and < 3.1) which only has base64.encodestring().

[pdecat]

Hi @venth, sorry this wasn't ready to merge as I did not yet fix the code compatibility for python 3.9-dev while maintaining backward compatibility with 2.7 and 3.1.

[venth]

I’ll revert the commit then

…

Wiadomość napisana przez Patrick Decat ***@***.***> w dniu 03.07.2020, o godz. 15:00: Hi @venth, sorry this wasn't ready to merge as I did not yet fix the code compatibility for python 3.9-dev while maintaining backward compatibility with 2.7 and 3.1. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

[venth]

Commit reverted. Sorry, I was too hasty :)