[PROPOSAL] remove Python 2 support

[PhilipMay]

see this discussion: #120 (review)

This should be changed for example:

opensearch-py/.github/workflows/ci.yml

Line 42 in 4056fa0

python-version: [2.7, 3.5, 3.6, 3.7, 3.8, 3.9]

[PhilipMay]

what do you think @dtaivpp @VijayanB

[VijayanB]

Since python 2.x support is ended, i agree that we should also move forward with python 3.x support only. I am leaning towards creating next major version and remove python 2 support starting 2.0 and keep 1.x only for high severity security fixes.
@dblock Can you provide feedback?

[wbeckler]

@VijayanB Do you know if keeping python 2.7 in there is breaking anything in OpenSearch v 1.x today? E.g. is it causing flakier tests or build issues?

[PhilipMay]

btw.: version 3.5 and 3.6 and also unsupported now...

[wbeckler]

Does anyone have other thoughts on the pros/cons of keeping these versions supported?

[dblock]

My general recommendation is to remove versions when they are both EOL and it's actually removing some kind of overhead (e.g. we can't adopt a syntax that's only Python 3.x), so I tend to do it while bumping a major version per semver because of other changes. It looks like EOL is true for Python <=3.6, so that's easy. Are there any actual advantages of removing 2.x support, or major changes we'd like to make that no longer work with older Python? @PhilipMay

[dblock]

Closing in favor of #430 which is just a more complete version of this.