title: In Flutter on adding custom font, FontWeight is not affecting the text
body: <p><a href="https://i.stack.imgur.com/mXjV6.png" rel="noreferrer">image pubspec</a>
  I want to set <code>Noir Pro</code> as the default font family for my flutter app.</p>
  <p>Default Roboto fontFamily changes to NoirPro but the font weights <code>e.g(.w400,w500,w600)</code> are not working correctly . I'm unable to find any other online help. And this is getting me frustrated</p>
  <p>In <code>pubspec.yaml</code></p>
  <pre><code>fonts:
      - family: NoirPro
        fonts:
          - asset: resources/fonts/NoirPro_Light.ttf
            weight: 300
          - asset: resources/fonts/NoirPro_Normal.ttf
            weight: 400
          - asset: resources/fonts/NoirPro_Medium.ttf
            weight: 500
          - asset: resources/fonts/NoirPro_Bold.ttf
            weight: 700
          - asset: resources/fonts/NoirPro_Heavy.ttf
            weight: 800
  </code></pre>
  <p><code>In main.dart</code></p>
  <pre><code> theme: ThemeData(
            fontFamily: 'NoirPro',
            canvasColor: Colors.white,
          ),
  </code></pre>