Updated CMake version to 3.20.5 Zephyr is increasing the minimum required CMake version to 3.20.0. Therefore docker needs to be updated accordingly, and 3.20.5 is the latest in the 3.20 series. See also: https://github.com/zephyrproject-rtos/zephyr/pull/37575 Signed-off-by: Torsten Rasmussen <[email protected]>