fix: Restore information about supported Python versions

[untitaker]

As part of #1066 this
information was lost.

[MimiDumpling]

👍

[vladlutkov]

But sentry_sdk/integrations/aiohttp.py, sentry_sdk/integrations/sanic.py and sentry_sdk/integrations/tornado.py have python 3.5+ keyword async

[untitaker]

@vladlutkov certain integrations have stricter version requirements. aiohttp supports 3.5+ so this integration only works on 3.5+. When somebody doesn't use the integration the file is not imported.

(for tornado we only support tornado versions that require 3.5+)

[untitaker]

We are using this SDK with Python 2.7 and Django 1.8 (previously 1.6) in production for sentry.io :) This works because we never import tornado/sanic/aiohttp related integrations

[vladlutkov]

In the case of aiohttp yes it's true, but tornado supports python2.7. Can you write restrictions for integrations?

[untitaker]

Sorry, yes, for Tornado we additionally require a minimum version of Python 3.6 because of contextvars support.

Integrations have their own requirements documented at e.g. https://docs.sentry.io/platforms/python/tornado/, I will note this here.

[vladlutkov]

Thanks

[untitaker]

I think it's possible that the strict Python version requirements of the integration for Tornado are not necessary or easily avoidable. But it would probably require code changes.

[untitaker]

re-requesting review just to make sure

[MimiDumpling]

👍