implprefix DeprecationWarning with pluggy 0.7.1

[edmorley]

Hi!

pluggy v0.7.1 has deprecated the implprefix argument:

• https://github.com/pytest-dev/pluggy/blob/master/CHANGELOG.rst#pluggy-071-2018-07-28
• Deprecate implprefix pytest-dev/pluggy#144

Treeherder marks warnings as errors, which causes the following failures from PyPOM:

DeprecationWarning: Support for the `implprefix` arg is now deprecated and
will be removed in an upcoming release. Please use HookimplMarker.

(Full log: https://travis-ci.org/mozilla/treeherder/jobs/409417404#L901)

The usage within PyPOM is here:

PyPOM/pypom/view.py

Line 20 in 697ae6a

self.pm = PluginManager('pypom', implprefix='pypom_')

We can temporarily ignore this DeprecationWarning via pytest's filterwarnings, however it would be good to fix upstream at some point.

[davehunt]

@edmorley this should be fixed by #92 but I'm on PTO for a week from tomorrow so I'd rather not do a release when I'm not around to deal with any potential issues. Are you okay with waiting on this?

[edmorley]

Yeah no rush at all (we've added a temporary filterwarnings entry for it); thanks for opening the PR :-)

[davehunt]

Fixed in PyPOM v2.1.0 by #92

[edmorley]

Many thanks :-)