title: disable/enable select depending on value vuejs
body: <p>i have 2 select fields:</p>
  
  <p>first field:</p>
  
  <pre><code>ns-dropdown-item(item-id="6")    
    ns-select(:placeholder="$t('users.role')", v-model="newLeader.role",
      :options="roleOptions", @change="activeIfCoororMan")
  </code></pre>
  
  <p>second field is disable</p>
  
  <pre><code>ns-dropdown-item(item-id="7")    
    ns-select(:placeholder="$t('users.client')", v-model="client", 
      :options="clients", :disabled="true")
  </code></pre>
  
  <p>this is my vue data:</p>
  
  <pre><code>export default {
    template: template(),
    data() {
      return {
        newLeader: null,
        client: null,
        clients: [],
        errors: {},
        roleOptions: [
          {value: 'coordinator', label: this.$t('users.roleOptions.coordinator')},
          {value: 'manager', label: this.$t('users.roleOptions.manager')},
          {value: 'leader', label: this.$t('users.roleOptions.leader')},
          {value: 'leader_admin', label: this.$t('users.roleOptions.leader_admin')}
        ]
      };
    },
    methods:  {
      activeIfCoororMan() {
        if(this.newLeader.role === 'manager' || this.newLeader.role === 'coordinator') {
          console.log("remove-disabled")
        } else {
          console.log("stay-disabled")
        }
      },
    }
  }
  </code></pre>
  
  <p>when i'm choosing in first select <strong>coordinator</strong> or <strong>manager</strong>, i can see in console: <strong>remove-disable</strong>. But, i would like change <code>:disable</code> attribute from second field to <code>false</code>.</p>
  
  <p>Thank you</p>