ci: Switch to CI image 0.23.3

This commit updates the CI workflows to use the CI image 0.23.3, in
order to pull in the Zephyr SDK 0.14.2 and other minor enhancements
and bug fixes detailed in the docker-image release notes.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>
7 files changed