CODEOWNERS: add ownership of STM32 quadrature decoder driver
CODEOWNERS: add ownership of STM32 quadrature decoder driver

Adding myself as the code owner for the STM32's quadrature encoder
driver

Signed-off-by: Valerio Setti <6ba64a6eaf9a2e428a6a18c107ce3eef394cd7be@baylibre.com>

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