Update CONTRIBUTING.md
Update CONTRIBUTING.md

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IATkachenko/gallery,setnes/gallery,tahaalibra/gallery,imjalpreet/gallery,interfasys/galleryplus,owncloud/gallery,imjalpreet/gallery,desaintmartin/gallery,viraj96/gallery,imjalpreet/gallery,viraj96/gallery,owncloud/gallery,setnes/gallery,setnes/galleryplus,IATkachenko/gallery,setnes/gallery,desaintmartin/gallery,viraj96/gallery,desaintmartin/gallery,owncloud/gallery,tahaalibra/gallery,interfasys/galleryplus,IATkachenko/gallery,tahaalibra/gallery,interfasys/galleryplus,owncloud/galleryplus,owncloud/galleryplus,owncloud/galleryplus,setnes/galleryplus,setnes/galleryplus