[Spec::DSL] Add check for singular form of the authors attribute
[Spec::DSL] Add check for singular form of the authors attribute

orta/Core,k0nserv/Core,AdamCampbell/Core,dnkoutso/Core,gabro/Core,CocoaPods/Core,brianmichel/Core,Ashton-W/Core,dacaiguoguogmail/Core