Integrate ABI jobs in Github

[j-rivero]

The pull request change how ABI jobs are triggered:

• Before, it was a conditional step in compilation jobs if target branch was different than master
• After: the abi job integrates itself in github calls only if the target branch is a supported branch (major version branches)

I'm leaving the same parameters as before to be able to run builds manually in the same way.

Testing:

Be careful to run dsl changes on Jenkins since they will affect production code. I've used my fork to check:

• Test PR with ABI breaking against sdf9 Break ABI yes. For teting of course j-rivero/sdformat#1
• Test PR with no ABI breaking changes in sdf8 Do nothing to ABI in sdf8 j-rivero/sdformat#2

All DSL runs fine on my local system and the produced xml for branches seems fine to me.

Closes #191

[chapulina]

Nice! I haven't really tested it, but the SDFormat results look promising!

[scpeters]

I just tested the with gazebosim/sdformat#301, and it's not working:

https://build.osrfoundation.org/job/sdformat-abichecker-any_to_any-ubuntu_auto-amd64/834/

https://build.osrfoundation.org/job/_dsl_sdformat/883/console

[scpeters]

it looks like that job doesn't have the GITHUB variable set, but it also isn't setting the SRC_BRANCH or DEST_BRANCH variables

[j-rivero]

it looks like that job doesn't have the GITHUB variable set,

Ouch, my bad sorry. I've merged #223 to help fixing it.

but it also isn't setting the SRC_BRANCH or DEST_BRANCH variables

I think it is a cosmetic thing for the build descriptions and should not stop of the build to be complete, although I need to fix it.

Seems to work now:

[scpeters]

thanks for the quick fix!

[scpeters]

I can't figure out why the following comment didn't start an ign-physics ABI checker job:

• Set slip compliance gazebosim/gz-physics#56 (comment)