Use Bookworm image instead of a non LTS Ubuntu image

During the rebase on bookworm, the image used was updated to Ubuntu 23.04 (0850575e) which is a non LTS version and will be EOL at the end of January 2024. Instead, use Bookworm which is supported until 2028 (LTS).

We will need to backport this change to v2024 to avoid failure when ubuntu:23.04 won't be available anymore.

Signed-off-by: Dylan Aïssi dylan.aissi@collabora.com