0.5.12 — install the sensor library, fix a lying diagnostic

Fixed

• The RPi.bme280 library actually gets installed now. 0.5.11 fixed the pip line, but the updater loads its own code before checking out the target — so a change to how it installs takes effect on the following update. This is that following update.
• A pin factory of "NoneType" is no longer reported as if it were a fault. gpiozero resolves its backend on first use, so asking before any pin has been touched legitimately returns nothing. The number that matters comes from the pulse itself, which asks after the pin exists.

If your heater test does nothing

The pulse now tells you which backend drove the pin. LGPIOFactory means real Pi 5 hardware access — the pin genuinely went high, and the problem is electrical rather than software. Most commonly: an LR7843 module's control header has three pins (SIG, VCC, GND) and the VCC is unconnected, so the onboard LED and gate driver have no supply.