Upgrade to Heroku-24 and Python 3.12

[simonw]

Spotted in the deploy logs:

This app is using the Heroku-22 stack, however a newer stack is available.
To upgrade to Heroku-24, see:
https://devcenter.heroku.com/articles/upgrading-to-the-latest-stack

https://devcenter.heroku.com/articles/upgrading-to-the-latest-stack

[simonw]

From those upgrade logs:

-----> Building on the Heroku-24 stack
-----> Using buildpack: https://github.com/heroku/heroku-buildpack-python.git
-----> Python app detected
-----> Using Python version specified in runtime.txt
 !     
 !     A Python security update is available! Upgrade as soon as possible to: python-3.11.10
 !     See: https://devcenter.heroku.com/articles/python-runtimes
 !     
-----> Stack has changed from heroku-22 to heroku-24, clearing cache

[simonw]

https://devcenter.heroku.com/articles/python-support#supported-runtimes

I'm going to upgrade to:

python-3.12.6

[simonw]

Tests failed:

ModuleNotFoundError: No module named 'pkg_resources'