Update REP 2001 with up-to-date packages for Galactic

[cottsay]

The entities in these lists are actually repositories and not packages, but the lists have nevertheless changed a fair amount since last revised.

I generated the lists with cobbled together queries like this:
for i in $(colcon list --packages-up-to desktop --packages-skip-up-to ros_base -p); do cd /opt/ros_src/galactic/$i && git rev-parse --show-toplevel; done | sort | uniq | awk -F/ '{ print $NF }' | sort | xargs echo | sed 's/ /, /g'

[clalancette]

I appreciate what you've done here, but there are two issues:

1. Are these changes backwards compatible all the way to Bouncy? The title of this article is "ROS Bouncy and newer variants", so in theory anything we change here should be backwards compatible.
2. This entire file is kind of redundant. That is, shouldn't the contents of this be "see https://github.com/ros2/variants for a list of packages"? Alternatively, can we auto-generate this based on what is in variants?

(separately, I realize that we haven't branched off https://github.com/ros2/variants for foxy and galactic. It might be a good idea to do that)

[cottsay]

Are these changes backwards compatible all the way to Bouncy?

Absolutely not. That said, the current state is not correct for any of the currently supported ROS 2 distros. Given the choice, I'd rather we were aligned between our spec and our supported distros rather than our EOL ones. I'm open to suggestions for how to do both.

can we auto-generate this based on what is in variants?

That's...what my bash-foo did.

[clalancette]

Given the choice, I'd rather we were aligned between our spec and our supported distros rather than our EOL ones.

Agreed, but...

I'm open to suggestions for how to do both.

One thing we've done in the past is to have a different REP for variants in different ROS distributions. For instance, for ROS 1 we have https://www.ros.org/reps/rep-0131.html , https://www.ros.org/reps/rep-0142.html , and https://www.ros.org/reps/rep-0150.html . Maybe we should do something similar here.

That's...what my bash-foo did.

Yeah, but I was thinking about doing it at "compile" time for the HTML pages (for lack of a better word). Honestly I don't know how these REP files become HTML pages over at https://www.ros.org/reps/ , but it would be nice if this just automatically updated. But I guess combined with what I said above, this doesn't make much sense.

[ros-discourse]

This pull request has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/core-base-and-desktop-releases/20267/2

[sloretz]

The entities in these lists are actually repositories and not packages,

That part is surprising because I thought repository names with more than one package could be arbitrary. In the ROS 1 reps I think they are packages or metapackages. Can we either go with package names, or change the document to say they are repositories?

[clalancette]

This was superseded by #327, so closing it out.