message: (pd) fix index.html css <link>
diff: <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Opentrons Protocol Designer Prototype</title>
  - <link rel="stylesheet" src="/bundle.css">
  + <link rel="stylesheet" href="./bundle.css" type="text/css">
  </head>
  <body>
  <div id="root"></div>
  