devel/py-pytest: add portepoch

In 46a663d44cb038c4b5fcca21f1c0151db0e8302e 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