如何使用vee-validade更改axios后捕获中的规则

import { ValidationObserver, ValidationProvider } from 'vee-validate';
import axios from 'axios';

data() {
  return {
    form: {
      username: '',
      password: ''
    },
    rules: {
      username: 'required|min:6',
      password: 'required|min:8'
    }
  };
},

<ValidationObserver ref="observer">
  <form @submit.prevent="submitForm">
    <div>
      <label for="username">Username:</label>
      <ValidationProvider rules="username">
        <input type="text" v-model="form.username">
      </ValidationProvider>
    </div>
    <div>
      <label for="password">Password:</label>
      <ValidationProvider rules="password">
        <input type="password" v-model="form.password">
      </ValidationProvider>
    </div>
    <button type="submit">Submit</button>
  </form>
</ValidationObserver>

methods: {
  submitForm() {
    this.$refs.observer.validate().then(valid => {
      if (valid) {
        axios.post('/api/login', this.form).then(response => {
          // 处理响应数据
        }).catch(error => {
          // 处理错误
        });
      }
    });
  }
}