Somehow, this slipped through in #1513. We weren't inheriting anymore,
so `branches` defaulted back to just `master`. This means we weren't
gating on most of the containerized builds anymore. Ouch!
It'd make sense to teach PAPR to allow some defaults across all
testsuites, even in the `inherit: false` case. Though it's tempting to
also just change the hardcoded PAPR default to those branches since our
use of Homu + PAPR at this point is pretty ubiquitous, and it doesn't
really hurt for the ones that don't use it.
Closes: #1536
Approved by: cgwalters
We do already have `http-headers`, which potentially could be used to
allow clients to completely override the field, but it seems like the
more common use case is simply to append.
Closes: #1496
Approved by: cgwalters
Allow users to pass `<remote>:` to list all refs we have locally
belonging to `<remote>`. Also (re-)allow the similar `<remote>:.` syntax
for backwards compatibility with flatpak.
Closes: #1500
Approved by: cgwalters
Jonathan Lebon