title: Flutter increase height of TextFormField
body: <p>I am creating a Flutter app. i made the design like this. 
  <a href="https://i.stack.imgur.com/46fUD.png" rel="noreferrer"><img src="https://i.stack.imgur.com/46fUD.png" alt="enter image description here"></a></p>
  
  <p>My TextFormField form field for email and password heights are small. I want it to be the same size of the button.</p>
  
  <pre><code>final email = TextFormField(
      keyboardType: TextInputType.emailAddress,
      autofocus: false,
      initialValue: 'sathyabaman@gmail.com', 
      style: new TextStyle(fontWeight: FontWeight.normal, color: Colors.white),
      decoration: InputDecoration(
        hintText: 'Email', 
        contentPadding: EdgeInsets.fromLTRB(20.0, 10.0, 20.0, 10.0),
        border: OutlineInputBorder(
          borderRadius: BorderRadius.circular(32.0)
        ),
      ),
    );
  </code></pre>
  
  <p>Whats the syntax for the height in text form field.</p>