This plugin is now officially a part of OBS 26.1 🎉🎉🎉. Unless you really know what you're doing you probably don't want to use this plugin. If you already have this plugin installed, you should uninstall it before upgrading to OBS 26.1. Simply run:
sudo rm -rf /Library/CoreMediaIO/Plug-Ins/DAL/obs-mac-virtualcam.plugin
sudo rm -rf /Library/Application\ Support/obs-studio/plugins/obs-mac-virtualcam
Then head over to the OBS Studio GitHub to get the latest release.