The nightly jobs have a `workflow_dispatch` action, which means you can
kick the job off on any branch. But the build steps has the branch to
build on hardcoded. I would like to be able to build windows and mac
builds without having a local build environment setup.
The docs for the checkout action says it default to the main branch,
so the scheduled actions should keep working fine. But now we'll be able
to create builds off of other branches too.
docs: https://github.com/actions/checkout#usage
ref: https://github.com/qutebrowser/qutebrowser/issues/7989
dc072a7825