Add pytest.markers to pyproject.toml

[jerempy]

Thank you for contributing to Pipenv!

The issue

This is to help silence most of the warnings when running pytest. Some test files when run individually would yield 70+ warnings about unreigstered custom pytest.marks.

https://github.com/pypa/pipenv/blob/master/peeps/PEEP-000.md

The fix

I registered them in the pyproject.toml per this: https://docs.pytest.org/en/stable/how-to/mark.html

I gave them a description as best as I could tell from what the tests were doing.

I didn't include all, but most of them. I left out ones that there were only a couple of.
running pipenv run pytest --markers
will yield (in addition to the baked in markers):

@pytest.mark.install: tests having to do with `pipenv install`
@pytest.mark.needs_internet: integration tests that require internet to pass
@pytest.mark.basic: basic pipenv tests grouping
@pytest.mark.dev: tests having to do with dev and dev packages
@pytest.mark.system: related or interacting with the os
@pytest.mark.utils: grouping of pipenv utility functions
@pytest.mark.cli: test grouping that relate to command line like `pipenv --flag args`
@pytest.mark.requirements: tests that save and alter pip requirements
@pytest.mark.run: tests that run or execute python through pipenv
@pytest.mark.script: grouping of tests that execute scripts
@pytest.mark.keep_outdated: when an activity is supposed to keep something out of date
@pytest.mark.lock: tests that interact with pipenv lock
@pytest.mark.markers: pipenv environment markers
@pytest.mark.vcs: tests integration with pipenv and vertsion control systems
@pytest.mark.project: tests with the project object
@pytest.mark.sync: related to `pipenv sync`
@pytest.mark.rrule: relating to rrules (as in recurring time)
@pytest.mark.tzoffset: timezone offset
@pytest.mark.gettz: tests with gettz (get timezone) from dateutil lib
@pytest.mark.tzstr: timezone string
@pytest.mark.extras:
@pytest.mark.extended:
@pytest.mark.ext: extra non-categorized tests

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.

[oz123]

Can you please add a news fragment?