[build.snapcraft.io] Allow multiple variants of a source


We have a snap which gets a new build whenever anything it committed to that project’s GitHub, its based on CPython. We want a variant of that snap based on PyPy that also gets built whenever something is committed to project’s master.

How can we use build.snapcraft.io to use two different snapcraft.yaml files when something is committed to our project’s master ?

This is the first build yaml https://github.com/crossbario/crossbar/blob/master/snap/snapcraft.yaml
and here is the second https://github.com/om26er/crossbar-pypy-snap/blob/master/snap/snapcraft.yaml (which currently lives out of tree)