Motivation

This PR contains all changes necessary to upgrade our Python version for the runtime from 3.11 to 3.12.
Similar to previous updates:

• Update to Python 3.11 #8087
• Upgrade python version to 3.10 #5632

Changes

• Update all CircleCI runners (which use Python 3.12.1 by default).
• Update all GitHub actions to install Python 3.12 instead of Python 3.11.
• Update the dockerfile base image to the latest sha digest of Python 3.12.2.
• Update all references to virtual environments which contain the Python version (f.e. /usr/lib/localstack/python-packages/lib/python3.12/site-packages).
• Update the Lambda Runtime version used for local execution (in the runtime of LocalStack itself) from 3.11 to 3.12.
  Impact
• Update the pinned dependencies (they need to be generated with the right version).
• Update the .python-version file for pyenv

This PR only updates the runtime version of LocalStack itself. The LocalStack CLI will still be compatible with Python 3.8+.
However, Python Initialization Hooks and LocalStack Extensions will then run in a Python 3.12 environment instead of Python 3.11.

TODO

• js2py is currently not compatible with Python 3.12.
  • KeyError in python3.12.0 PiotrDabkowski/Js2Py#317
  • Fix bytecode for Python 3.12 PiotrDabkowski/Js2Py#327
• Verify that the tests are all green / all libraries and our code are compatible.
• Verify that this change is compatible with our downstream projects.