schemas/IGCFileSchema: Add "filename" attribute
schemas/IGCFileSchema: Add "filename" attribute

Harry-R/skylines,Turbo87/skylines,skylines-project/skylines,Turbo87/skylines,shadowoneau/skylines,skylines-project/skylines,skylines-project/skylines,RBE-Avionik/skylines,RBE-Avionik/skylines,shadowoneau/skylines,Harry-R/skylines,Turbo87/skylines,shadowoneau/skylines,kerel-fs/skylines,Turbo87/skylines,Harry-R/skylines,RBE-Avionik/skylines,kerel-fs/skylines,RBE-Avionik/skylines,kerel-fs/skylines,shadowoneau/skylines,skylines-project/skylines,Harry-R/skylines