Fixed the config string for autoprefixer to use "last 3 versions" (plural).
Fixed the config string for autoprefixer to use "last 3 versions" (plural).

jakefleming/mezzotent,greypants/gulp-starter,jakefleming/mezzotent,cubbrio/cubbrio.github.io,vigetlabs/gulp-starter,clarkras/table_merge,vigetlabs/gulp-starter,jakefleming/mezzotent,cubbrio/cubbrio.github.io,cubbrio/cubbrio.github.io,clarkras/table_merge,clarkras/table_merge,jakefleming/mezzotent,vigetlabs/gulp-starter,greypants/gulp-starter,greypants/gulp-starter,vigetlabs/gulp-starter,clarkras/table_merge,greypants/gulp-starter,cubbrio/cubbrio.github.io,clarkras/table_merge