fix: 解决picker组件columnchange事件和change事件错乱的问题

src/core/view/components/picker-view-column/index.vue

@@ -132,7 +132,6 @@ export default {
   render (createElement) {
     this.length = (this.$slots.default && this.$slots.default.length) || 0
     return createElement('uni-picker-view-column', {
-      staticClass: '_picker-view-column',
       on: {
         tap: this._handleTap
       }

src/core/view/components/picker/index.vue

@@ -107,10 +107,6 @@ export default {
     disabled: {
       type: [Boolean, String],
       default: false
-    },
-    customItem: {
-      type: String,
-      default: ''
     }
   },
   data () {
@@ -205,7 +201,7 @@ export default {
       }
     },
     columnchange (args) {
-      this.$trigger('change', {}, args)
+      this.$trigger('columnchange', {}, args)
     },
     cancel (args) {
       this.visible = false

src/platforms/h5/components/app/popup/picker.vue

@@ -130,10 +130,6 @@ export default {
       type: [Boolean, String],
       default: false
     },
-    customItem: {
-      type: String,
-      default: ''
-    },
     visible: {
       type: Boolean,
       default: false