Should we pin the version numbers of dependencies for the demos?

[mkhansenbot]

Currently the repos files for the moveit2 and navigation2 dependencies use branch names (humble, ros2, etc). Should we pin those to specific version numbers that are known to work?

The pro is that then we ensure we don't break the demos. The con is that we may break the demos when the source code for moveit2 or nav2 "humble" branches move forward.

[mkhansenbot]

Added to next milestone (proposed) humble-2024.04.0

[Bckempa]

Addressed in Nav2 by #152 and true demo containers have been moved and pinned, so this issue only needs to address moveit2. @EzraBrooks or @dsobek?