Merge branch 'feature/webpack2' into release/5.5.1

@@ -2,7 +2,7 @@
     "presets": [
     	["env", {
       		"targets": {
-        		"browsers": ["> 1%"]
+        		"browsers": [">1%", "android >=4", "ios >=8"]
       		}
     	}]
   	]

@@ -106,7 +106,7 @@ exports.postcssPlugin = (et) => {
             propWhiteList: [] // 属性名称为空，表示替换所有属性的值
         }),
         autoprefixer({
-            browsers: ['> 1%']
+            browsers: ['> 1%', 'android >=4', 'ios >=8']
         }),
         postUse({
             modules: ['postcss-clearfix', 'postcss-crip', 'postcss-short', 'postcss-center', 'postcss-position']