We use github action to test our code

We install in the very latest off all tools including pip
python -m pip install --upgrade setuptools wheel
python -m pip install pip

This worked (and still) fine with opencv-python 4.5.5.64

it failes
File "/tmp/easy_install-otpfl9qw/opencv-python-4.6.0.66/setup.py", line 10, in
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
ModuleNotFoundError: No module named 'skbuild'

Only changing our requirements to
opencv-python < 4.6.0.66

and the exact same workflow works.

Our github action
"runs-on: ubuntu-20.04"