Test suite broken with webdriver_manager >= 4.0.0: ChromeType import error

[bwagner]

Running pytest tests/test_browsers.py fails on import:

ImportError: cannot import name 'ChromeType' from 'webdriver_manager.core.utils'

ChromeType moved to webdriver_manager.core.os_manager in >= 4.0.0.
Fix is a one-line import change — PR to follow.