When $PIMORONI_PICO_FETCH_FROM_GIT environment variable is set
cmake script will fetch on the go git repository and use it to
build your project.
User can additionally use $PIMORONI_PICO_FETCH_FROM_GIT_PATH to
specify target directory for source code of fetched SDK.
This patch was inspired by external/pico_sdk_import.cmake from
official C/C++ pico-sdk repository.
Check for pimoroni-pico next to the pico sdk, then next to the project. If neither exist, fail with an error that tells the user to set PIMORONI_PICO_PATH.
Part of the fix for the Pico Boilerplate breakage mentioned in pimoroni/pico-boilerplate#8
This file is included here for posterity and because it's existence is used to validate PIMORONI_PICO_PATH
thinkofher