Switch from deprecated toml library

[CyberTailor]

The replacement is Python's 3.11 tomllib module and tomli package for older versions.

[anthrotype]

thanks for the reminder. yes we should switch at some point. Are the APIs similar enough that one can use these as drop-in replacements?
Are you volunteering to send on a PR? :)

[anthrotype]

I'm afraid but I have encountered a major issue with tomlkit python-poetry/tomlkit#309, thus I will have to revert the #452 PR for now.

[anthrotype]

@CyberTailor In this issue you mentioned tomli but in the PR #452 you ended up using tomlkit. May I ask why?

[anthrotype]

for reference, these are the CI build failures that I was seeing, which led me to file the above mentioned issue python-poetry/tomlkit#309:

https://github.com/googlefonts/nanoemoji/actions/runs/5762993401/job/15623882139

I pushed the revert commit to this PR #462

[CyberTailor]

In this issue you mentioned tomli but in the PR #452 you ended up using tomlkit. May I ask why?

tomli has no write support

[anthrotype]

https://pypi.org/project/tomli-w/