ci: add v3 release branch to workflow triggers

[choppsv1]

Github needs to see all the triggers on the master/main branch version of this file for them to work.

[choppsv1]

I don't think this PR is going to pass CI now that upstream libyang master has moved to libyang v4.

I discovered with my first PR against the b_3.x branch that the action triggers have to exist on the master version of the workflow file for them to be used. Notice they didn't run on #162 We need to have both master and b_3.x as triggers in the file.

[choppsv1]

Hmm Ok learning more here. I added - master back to the triggers on the branch copy of the workflow file and the actions ran, so apparently the only thing blocking the action from running was that it disabled the master trigger.