A changeset to switch to python-requests has been merged into pywikibot-core.
https://gerrit.wikimedia.org/r/#/c/213977/
Note that config.proxy support doesnt exist. requests will read your environment variables to find a proxy. If this doesnt work for you, please raise a bug.
A minimum version of requests is not specified anywhere. If you find a problem with older versions of requests, please raise bugs and we'll either try to fix them or set a minimum supported version if a fix isnt easy.
Please test so we can fix any critical problems before releasing PR2 into pip.
Especially retest any problem which was http related, as it may now be fixed ;-)