Add pipeline configuration for Woodpecker CI. This tells Woodpecker how
to build our firmware, so it can automatically generate firmware images
for all commits to the master branch.
Continuous integration not only helps spotting build errors early, but
also allows non-developers to test the firmware during development.
Signed-off-by: Fabian Bläse <fabian@blaese.de>
Acked-by: Christian Dresel <freifunk@dresel.systems>
