ci: add basic integration test for pmb

Yes, I know this is crude/basic, but others are welcome to improve it later. I think we need some integration testing asap, and this is better than nothing :D

.ci/integration.sh

@@ -23,8 +23,10 @@ ui="phosh"
 ./pmbootstrap.py config device "$device"
 ./pmbootstrap.py config ui "$ui"
 
+# NOTE: --no-image is used because building images makes pmb try to
+# "modprobe loop". This fails in CI.
 echo "Building $ui image for $device"
-./pmbootstrap.py -y install --zap --password 147147
+./pmbootstrap.py -y install --zap --password 147147 --no-image
 
 echo "Building $ui image for $device, with FDE"
-./pmbootstrap.py -y install --zap --password 147147 --fde
+./pmbootstrap.py -y install --zap --password 147147 --fde --no-image