scripts: get_maintainer: Use SafeLaoder for yaml
scripts: get_maintainer: Use SafeLaoder for yaml

Using SafeLoader is preferrable where possible

Signed-off-by: Moritz Fischer <b8d4025d2b8bf5751b0cdbeb665b5d4746bed72d@google.com>

galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr