scripts: ci: add vermin (min python version check)

Add a compliance check that allows to flag when a given file requires a
Python version higher than 3.10 (minimum supported version in Zephyr at
the time of writing) since not all Python scripts are tested against
3.10 in CI and we want to avoid introducing changes that could break
users.

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>