去除占位符

src/pages/parkingFee/vehicleManagement.vue

@@ -130,7 +130,7 @@
       v-if="licensePlateList.length && licensePlateList.length < 3"
       @click="toAdd"
     >
-      <div class="add_plate_btn">+添加车牌号2</div>
+      <div class="add_plate_btn">+添加车牌号</div>
       <div class="btnpb"></div>
     </div>
   </div>