message: making link https
diff: <title>Simple HTML</title>
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <!-- LOAD Tone.js from unpkg -->
  - <script src="http://unpkg.com/tone"></script>
  + <script src="https://unpkg.com/tone"></script>
  <script>
  function playNote() {
  // create a synth
  