Drop %YAML version directives from include files

It seems that gitlab is doing something unfortunate (read: stupid) with their processing of yaml includes, so if we have %YAML version directives in either include files or including ones, they fail to parse as invalid yaml and therefore breaks the CI pipelines, but only for SOME projects, like modio-api but not for submit.

This is funny, in the not so haha sense, and may be related to gitlab-org/gitlab!115703 (merged) but it's uncertain.