title: stencil change @Prop() detection
body: <p>How can I detect prop changes in stencil, in angular is something like this:</p>
  
  <p>But I don't know how is in stencil.</p>
  
  <pre><code>import { Component, Input, OnInit } from '@angular/core';
  
  @Component({
    selector: 'my-name',
    template: `
        &lt;h2&gt;First name: {{name}} ({{_name}})&lt;/h2&gt;
    `,
  })
  export class ChildComponent implements OnInit {
    private _name: string;
    constructor() {}
  
    get name(): string {
      // transform value for display
      return this._name.toUpperCase();
    }
  
    @Input()
    set name(name: string) {
      console.log('prev value: ', this._name);
      console.log('got name: ', name);
      this._name = name;
    }
  
    ngOnInit() {
      console.log('on init');
      console.log(this._name);
    }
  }
  </code></pre>
  
  <p>I need to detect properties changes</p>