`opencv-python[-headless]` not installed automatically

[tuanpham96]

In a fresh venv environment, opencv-python[-headless] does not automatically install opencv-python. Doing pip show opencv-python or pip show opencv-python-headless shows nothing.

This is the final output for pip install dlc2nwb inside a fresh venv:

Successfully installed attrs-23.1.0 dlc2nwb-0.3 h5py-3.9.0 hdmf-3.8.0 jsonschema-4.18.4 jsonschema-specifications-2023.7.1 ndx-pose-0.1.1 numpy-1.25.1 pandas-2.0.3 pynwb-2.4.0 python-dateutil-2.8.2 pytz-2023.3 referencing-0.30.0 rpds-py-0.9.2 ruamel-yaml-0.17.32 ruamel.yaml.clib-0.2.7 scipy-1.11.1 six-1.16.0 tzdata-2023.3