www/py-requests: Update to 2.22.0

• Backport a patch from upstream that fixes the unittests in conjunction with devel/py-pytest >= 4.

• Remove obsolete CONFLICTS_INSTALL entry as www/py-requests1 no longer exists in the Ports tree.

This update includes a pinned urllib3 version bump to < 1.26, which clears
the way for a net/urllib3 update to 1.25.6 [1].

Changelog:

https://github.com/requests/requests/blob/v2.22.0/HISTORY.md

PR: 239302, 229322 [1]
Submitted by: swills (based on)
Approved by: koobs (maintainer)
MFH: 2019Q4