title: Cannot change border color in OutlinedButton
body: <p>I'm trying to change the border of my <code>OutlinedButton</code> in my <code>main.dart</code> but it doesn't seem to be working. I've been looking around and it seems like I need to add <code>BorderSide</code>. This is what my <code>outlinedButtonTheme</code> looks like:</p>
  <pre class="lang-dart prettyprint-override"><code>              outlinedButtonTheme: OutlinedButtonThemeData(
                  style: ButtonStyle(
                    backgroundColor: MaterialStateProperty.resolveWith&lt;Color&gt;(
                      (Set&lt;MaterialState&gt; states) {
                        if (states.contains(MaterialState.pressed)) {
                          return AppColors.SecondaryButtonPressed;
                        }
  
                        return AppColors.SecondaryButton;
                      },
                    ),
                    minimumSize: MaterialStateProperty.all&lt;Size&gt;(Size(335, 60)),
                    shape: MaterialStateProperty.all&lt;OutlinedBorder&gt;(
                        RoundedRectangleBorder(
                      side: BorderSide(
                          style: BorderStyle.solid,
                          color: AppColors.Primary,
                          width: 1), // &lt;-- this doesn't work?
                      borderRadius: BorderRadius.all(Radius.circular(12)),
                    )),
                    foregroundColor: MaterialStateProperty.all&lt;Color&gt;(
                        AppColors.SecondaryButtonText),
                    textStyle: MaterialStateProperty.all&lt;TextStyle&gt;(TextStyle(
                      color: AppColors.SecondaryButtonText,
                      fontSize: 14 * FONT_SCALE_FACTOR,
                      fontWeight: FontWeight.w600,
                    )),
                  ),
                ),
  </code></pre>
  <p>Shown above where BorderSide is. It doesn't seem like this is working at all.</p>