ci: plugins job fails due to conflicting pip requirements

[bluetech]

I will investigate it at some point unless some one else figures it out.

https://github.com/pytest-dev/pytest/runs/1154419687

Run tox -e plugins
.package create: /home/runner/work/pytest/pytest/.tox/.package
.package installdeps: setuptools>=42.0, setuptools-scm[toml]>=3.4, wheel
plugins create: /home/runner/work/pytest/pytest/.tox/plugins
plugins installdeps: anyio[curio,trio], django, pytest-asyncio, pytest-bdd, pytest-cov, pytest-django, pytest-flakes, pytest-html, pytest-mock, pytest-sugar, pytest-trio, pytest-twisted, twisted, pytest-xvfb
plugins inst: /home/runner/work/pytest/pytest/.tox/.tmp/package/1/pytest-6.0.1.dev208+g5cfd7c0dd.tar.gz
plugins installed: anyio==2.0.0,argcomplete==1.12.0,asgiref==3.2.10,async-generator==1.10,attrs==20.2.0,Automat==20.2.0,certifi==2020.6.20,chardet==3.0.4,constantly==15.1.0,coverage==5.3,curio==1.4,decorator==4.4.2,Django==3.1.1,EasyProcess==0.3,elementpath==2.0.3,glob2==0.7,greenlet==0.4.17,hyperlink==20.0.1,hypothesis==5.35.4,idna==2.10,importlib-metadata==2.0.0,incremental==17.5.0,iniconfig==1.0.1,Mako==1.1.3,MarkupSafe==2.0.0a1,mock==4.0.2,more-itertools==8.5.0,nose==1.3.7,outcome==1.0.1,packaging==20.4,parse==1.18.0,parse-type==0.5.2,pluggy==0.13.1,py==1.9.0,pyflakes==2.2.0,PyHamcrest==2.0.2,pyparsing==3.0.0a2,pytest @ file:///home/runner/work/pytest/pytest/.tox/.tmp/package/1/pytest-6.0.1.dev208%2Bg5cfd7c0dd.tar.gz,pytest-asyncio==0.14.0,pytest-bdd==4.0.1,pytest-cov==2.10.1,pytest-django==3.10.0,pytest-flakes==4.0.2,pytest-html==2.1.1,pytest-metadata==1.10.0,pytest-mock==3.3.1,pytest-sugar==0.9.4,pytest-trio==0.6.0,pytest-twisted==1.13.2,pytest-xvfb==2.0.0,pytz==2020.1,PyVirtualDisplay==1.3.2,requests==2.24.0,six==1.15.0,sniffio==1.1.0,sortedcontainers==2.2.2,sqlparse==0.3.1,termcolor==1.1.0,toml==0.10.1,trio==0.17.0,Twisted==20.3.0,typing-extensions==3.7.4.3,urllib3==1.25.10,xmlschema==1.2.4,zipp==3.2.0,zope.interface==5.1.0
plugins run-test-pre: PYTHONHASHSEED='1399037378'
plugins run-test: commands[0] | pip check
argcomplete 1.12.0 has requirement importlib-metadata<2,>=0.23; python_version == "3.7", but you have importlib-metadata 2.0.0.
ERROR: InvocationError for command /home/runner/work/pytest/pytest/.tox/plugins/bin/pip check (exited with code 1)

[nicoddemus]

This is due to importlib-metadata 2.0 being released yesterday, argcomplete pinning it to <2, and pip (old) solver failing to satisfy all requirements.

kislyuk/argcomplete#321

[nicoddemus]

Using the new pip's new dependency resolver seems to fix it: #7784 👍