ci: Add comment pointing to actionlint
ci: Add comment pointing to actionlint

If Github does not accept a workflow YAML file as intended,
actionlint is a very useful tool to help find out what is
wrong in the YAML file.

gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2