fix: python path

Balena seems to use 3.11 in this image. https://hub.docker.com/layers/balenalib/raspberry-pi-debian-python/bullseye-run-20221215/images/sha256-ef1449f6388354cc9381d0a76941b6dcd43210cd4e5c19dabc0774fdd4047eb5?context=explore

Dockerfile

@@ -81,7 +81,7 @@ RUN export DISTRO=bullseye-stable && \
 
 # This is the libmraa install location, because we are using venv
 # it must be added to path explicitly
-ENV PYTHONPATH="$PYTHONPATH:/usr/local/lib/python3.9/dist-packages"
+ENV PYTHONPATH="$PYTHONPATH:/usr/local/lib/python3.11/dist-packages"
 
 # Run start-gateway-config script
 ENTRYPOINT ["/opt/start-gateway-config.sh"]