Update constraints.txt to use fontmake==3.10.0

[anthrotype]

see googlefonts/fontc#1060

I created a new venv (using python 3.12 which I believe was the same used before to generate the current constraints.txt), then I run these commands

$ pip install -r ../fontc/resources/scripts/requirements.txt
$ pip freeze --exclude setuptools > constraints.txt

then I only git-added the modified lines and kept the comments at the top.

(we could alternatively use pip-compile script from pip-tools which would automate all of the above, without needing to create the temporary venv -- but i'm fine with keeping it thus for now)

[cmyr]

Looks good, let's see how this goes!