CircleCI is limiting how many runs we can do, which results in pipelines
randomly failing when we've used up the credits for this month.
Let's add a github workflow instead. Unfortunately github workflows are
a bit of a toy api, no support for YAML anchors or extending other jobs,
so there's a lot of duplication needed to get a job to do something.
The actions added in this patch help a bit to make the jobs easier to
understand (copied from libwacom).
This only runs on Ubuntu right now.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
