FormItem: v-bind:style -> :style (#11996)

packages/form/src/form-item.vue

@@ -8,10 +8,10 @@
     },
     sizeClass ? 'el-form-item--' + sizeClass : ''
   ]">
-    <label :for="labelFor" class="el-form-item__label" v-bind:style="labelStyle" v-if="label || $slots.label">
+    <label :for="labelFor" class="el-form-item__label" :style="labelStyle" v-if="label || $slots.label">
       <slot name="label">{{label + form.labelSuffix}}</slot>
     </label>
-    <div class="el-form-item__content" v-bind:style="contentStyle">
+    <div class="el-form-item__content" :style="contentStyle">
       <slot></slot>
       <transition name="el-zoom-in-top">
         <div