title: How can be the report opened automatically when test finishes
body: <p>I am running Serenity-js with cucumber and Angular CLI. </p>
  
  <p>I am using scripts in 'package.json' to execute the sequence of cleaning, testing and generating the report <code>"e2e2": "failsafe clean pretest protractor report"</code>.</p>
  
  <pre><code> //package.json
    .............
     "scripts": {
              "ng": "ng",
              "start": "ng serve",
              "build": "ng build",
              "test": "ng test",
              "lint": "ng lint",
              "e2e": "ng e2e",
              "webdriver-update": "webdriver-manager update",
              "protractor": "protractor ./protractor.conf.js",
              "clean": "rimraf target",
              "pretest": "serenity update",
              "report": "serenity run",
              "e2e2": "failsafe clean pretest protractor report"
     ................
  </code></pre>
  
  <p>Everything works fine but I want the report located in <code>target/site/serenity/index.html</code>  to be opened automatically when the test finishes.  </p>
  
  <p>How can I complete my script sequence with this functionality?</p>