Unable to override core integration

Hi!
I am currently working on extending a core integration (the tado integration to be specific) and while waiting for the PR to be merged and consequently released at the beginning of December, I wanted to install it on my local HA instance. I use HA supervised, so my config dir is in /usr/share/hassio/homeassistant. So, following the instructions from Integration file structure | Home Assistant Developer Docs I downloaded the code from the fork waiting to be merged (GitHub - Moritz-Schmidt/hass-core: 🏡 Open source home automation that puts local control and privacy first.) and copied over the tado integration folder to custom_components/. Also, I set the version in the manifest.json file (to 1.0.0 should that matter).

After restarting HA, the core integration will still be loaded instead of the custom integration. Does anyone have an idea what I could be missing here?