Bookworm/Pi5 Compatibility: Upgrade to latest boilerplate

[Gadgetoid]

Drop RPi.GPIO since it can no longer be relied upon.

Now sets a default i2c bus, and no longer attempts to auto detect (none of our libraries do).

Testing

If you're a Bookworm / Pi 5 user running into virtual environment or RPi.GPIO issues, you can try this library like so:

git clone https://github.com/pimoroni/sn3218-python -b repackage
cd sn3218-python
./install.sh --unstable

The ./install.sh script will create a pimoroni virtual environment that's shared between our products. (or use your existing venv if you've already activated one.)

For the reasons behind these changes and other information, see:

• Raspberry Pi OS Bookworm + Pep 668 boilerplate-python#13
• Migration to Pi 5 / Bookworm Progress boilerplate-python#16
• https://pimoroni.github.io/venv-python/