Task: Remove "pytest-forked" from dependencies (Python 3.7+)

[mdmintz]

Task: Remove pytest-forked from dependencies (Python 3.7+)

Now that pytest-xdist has dropped the pytest-forked dependency (pytest-dev/pytest-xdist#468 and https://pytest-xdist.readthedocs.io/en/latest/changelog.html#pytest-xdist-2-5-0-2021-12-10), SeleniumBase shouldn't require it either (for Python 3.7 and newer versions).

If people still need it, they should install it separately. (It wasn't very helpful on its own to begin with, as it usually caused other issues with other integrations.)

[mdmintz]

This was resolved in 4.15.10 - https://github.com/seleniumbase/SeleniumBase/releases/tag/v4.15.10