fix: 修复 input 动态设置 maxlength 报错的问题

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

@@ -132,7 +132,7 @@ export default {
       this.$emit('update:value', value)
     },
     maxlength (value) {
-      const realValue = this.realValue.slice(0, parseInt(value, 10))
+      const realValue = this.inputValue.slice(0, parseInt(value, 10))
       realValue !== this.inputValue && (this.inputValue = realValue)
     }
   },