chore(package): update gulp-autoprefixer to version 4.1.0 (#2719)

package.json

@@ -84,7 +84,7 @@
     "google-closure-compiler": "~20171203.0.0",
     "google-closure-library": "~20171203.0.0",
     "gulp": "~3.9.1",
-    "gulp-autoprefixer": "~4.0.0",
+    "gulp-autoprefixer": "~4.1.0",
     "gulp-browserify": "~0.5.1",
     "gulp-cheerio": "~0.6.2",
     "gulp-clang-format": "1.0.23",