devel/py-pytest: add portepoch

In 46a663d4 multiple reverts of updates
happend:
 * devel/py-pytest-flask downgrade from        6.2.4 -> 4.6.11
 * devel/py-pytest-translations downgrade from 3.1.0 -> 2.0.0
 * devel/py-pytest-xdist downgrade from        2.3.0 -> 2.3.0
 * devel/py-pytest-flask downgrade from        1.2.0 -> 0.15.1

Differential Revision:	https://reviews.freebsd.org/D34006
Approved by:		rene