Testing requirements are outdated

I'm going through the poetry.lock file in one of my projects and searching for packages that still use six in order to help the package maintainers drop support for python 2.7.

However, pytest-cov lists six as a testing requirement even though it does not support python 2.7. I also came across a couple of issues that I would like to let you know about.

setup.py says that:

six is required but it is not actually used in the project
process-tests is in setup.py but not in ci/requirements.txt
hunter was added in 0d75fd2 with no code dependency. I think this might be a local debugging tool that @ionelmc was using.

pytest-cov/setup.py

Lines 136 to 145 in 2c9f217

    
           extras_require={ 
        
               'testing': [ 
        
                   'fields', 
        
                   'hunter', 
        
                   'process-tests', 
        
                   'six', 
        
                   'pytest-xdist', 
        
                   'virtualenv', 
        
               ] 
        
           },

These dependencies were moved from tox which made them hard to track.

Thanks for digging those oversights up,now they can be resolved

The quickest way may be a PR with the fix

@RonnyPfannschmidt if process-tests is required but not in https://github.com/pytest-dev/pytest-cov/blob/master/ci/requirements.txt, then how were the tests being run?

The're used here:
https://github.com/pytest-dev/pytest-cov/blob/master/tests/test_pytest_cov.py#L16

I made a PR for six. I do like too provide a bit of help to random projects:

https://wiki.debian.org/Python3-six-removal

	extras_require={
	'testing': [
	'fields',
	'hunter',
	'process-tests',
	'six',
	'pytest-xdist',
	'virtualenv',
	]
	},