docs: Developers setup has a problem with py3cairo.pc

[joyously]

I am on Ubuntu 22.04 LTS and following the instructions in the Developers setup.

I used the Debian/Ubuntu command given for dependencies. It installed 11MB (I already had flatpak and python3-pip).

Then I used the command for developer requirements:
sudo pip3 install -r requirements.dev.txt
It started downloading and installing stuff. One message said
Requirement already satisfied: pycairo>=1.16.0 in /usr/lib/python3/dist-packages (from PyGObject~=3.44->-r requirements.txt (line 1)) (1.20.1)
But when building PyGObject, it stopped with an error:
Package py3cairo was not found in the pkg-config search path.

I tried to install it with pip3, but it could not find a matching distribution for py3cairo.

I don't really know what I'm doing with these tools, so how do I move forward and what needs to change in the docs?

[joyously]

FYI: I looked up pycairo and on their Getting Started page it says different versions are cached by pip.

You can force pip to re-build and re-install pycairo in this case:
pip3 install --force-reinstall --no-cache-dir pycairo

Once I did this, I reran the developer install for Diffuse, and it was successful.

I think the Developers setup page is a bit sparse on what all these tools are for.
Any ideas for debugging would be great.