Allow colcon release-in-container to use more that 1 cpu

[aosmw]

I noticed that the colcon release-in-container does a build that only uses 1 cpu.

Here is a related discussion that bloom is that way in order to make it work for the ros build farm use case.
ros-infrastructure/bloom#643

[Guillaumebeuzeboc]

Thanks for the feedback and the link.
In the case of the release-in-container we are building the packages in a deterministic order, so that shouldn't cause any issue.
Now I am more wondering if we should and how to integrate such a change in release-in-container.

I would probably be simpler if Bloom could get released with that change, since the project is not meant to diverge from upstream.

[aosmw]

The change, IF you decided to do it, could be allow debian/compat to be overwritten to a number (10 or even 13). other than what it currently defaults to after the bloom-generate call,

colcon-in-container/colcon_in_container/verb/release_in_container.py

Line 92 in 33551d2

f'bloom-generate {generator}'])

Here is a script where it is done with a simple echo 11 > debian/compat which is a comment in
ros-industrial/industrial_ci#697 (comment)

Turns out that 11 is not recommended. 10 would be enough to satisfy this issue. Automatically do the build in parallel.

[artivis]

I agree that I would prefer this to land in bloom rather than as a workaround here.

Linking the related bloom ticket: ros-infrastructure/bloom#643.