- Rely on shebang instead of setting shell in workflow
- Run whole install-dependencies.sh in sudo
- Use /bin/sh instead of bash
- set -e

The new step is added with `if: ${{ !cancelled() }}`, so the logs are
stored even when the build fails.

This will hopefully make CI runs more robust and recover stale workers.

This is required to build the next branch which requires rsync to be
available.

Rsync is a requirement for OpenWrt master and therefore our next
branch. Currently builds on x86-64 error out due to missing rsync:

/bin/sh: 1: rsync: not found

This enables build-testing only on master as well as next and release
branches.

This will be a useful precursor for continuous integration.

The gluon-web package is basically a stripped-down and refactored version
of the LuCI base.

This script will analyze the dependencies of Gluon's packages and output
them as a dot graph.