Add Humble to REP 2000

[audrow]

This PR adds an entry for Humble Hawksbill to REP 2000.

I tried to grab the relevant dependencies. For Ubuntu Jammy and Windows 10. These may change before Humble is released. Also, I've left RHEL 8 in, since it is currently supporting Rolling.

[clalancette]

Overall, this looks like a good start. I've left a couple of comments for improving things.

[clalancette]

This looks good to me now. I'd actually be inclined to add a note to the top of the new section saying "this is subject to change until April 2022", and then merge this PR in now. @audrow what do you think?

[audrow]

This looks good to me now. I'd actually be inclined to add a note to the top of the new section saying "this is subject to change until April 2022", and then merge this PR in now. @audrow what do you think?

Sounds good to me. I added a note and linked to the release timeline.

[clalancette]

This looks good to me, but let's keep this open for a few more days to collect any more feedback.

[ros-discourse]

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

https://discourse.ros.org/t/updating-rep-2000-for-humble-hawksbill/23077/1

[fujitatomoya]

lgtm

[ros-discourse]

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

https://discourse.ros.org/t/preparing-ros-2-rolling-for-the-transition-to-ubuntu-22-04/23124/1

[nuclearsandwich]

One small update to empy on Ubuntu but otherwise looks good.

[nuclearsandwich]

Oh, and @audrow consider adding yourself to the authors list https://github.com/ros-infrastructure/rep/blame/f99ff26309760947501c0927be1f4fbdafb6f10d/rep-2000.rst#L3

[audrow]

Oh, and @audrow consider adding yourself to the authors list https://github.com/ros-infrastructure/rep/blame/f99ff26309760947501c0927be1f4fbdafb6f10d/rep-2000.rst#L3

I didn't add myself because I didn't see previous ROS Bosses on there. @clalancette, do you think I should add myself as an author (and maybe the previous ROS Bosses, as well)?

[clalancette]

I didn't add myself because I didn't see previous ROS Bosses on there. @clalancette, do you think I should add myself as an author (and maybe the previous ROS Bosses, as well)?

I have no strong opinion on it. I'd just add yourself if you'd like to, but not add anyone else. Also, I would suggest updating the date at the top of the document. Once those two things are done, I'll suggest going ahead and merging this.

[Timple]

Is there any reason not to target c++20?

[clalancette]

Is there any reason not to target c++20?

There are a few reasons we don't think we are going to do this for Humble:

1. Every time we've switched C++ versions, it has taken some non-trivial amount of work to keep things working without warnings. Someone would have to step up to do that work.
2. All of our Tier 1 platforms probably support C++20 well, but not all of the Tier 2 and Tier 3 ones do.
3. Part of the ROS 2 community deals with safety certification, things like MISRA. Since those standards tend to lag behind the relevant standards, switching to a new C++ version too early can leave those users behind.