title: Flutter The named parameter 'colors' isn't defined in SweepGradient
body: <p>in my project i want to use <code>SweepGradient</code> and when i try to use with this definition i get error:</p>
  <pre><code>Context: Found this candidate, but the arguments don't match.
    const SweepGradient({
          ^^^^^^^^^^^^^
  </code></pre>
  <p>my code implementations:</p>
  <pre><code>static final BoxDecoration _gradientBorderDecoration = BoxDecoration(
    shape: BoxShape.circle,
    // https://brandpalettes.com/instagram-color-codes/
    gradient: SweepGradient(
      colors: [
        Color(0xFF833AB4), // Purple
        Color(0xFFF77737), // Orange
        Color(0xFFE1306C), // Red-pink
        Color(0xFFC13584), // Red-purple
      ],
    ),
  );
  </code></pre>
  <p><code>SweepGradient</code> construct class:</p>
  <pre><code>const SweepGradient({
    this.center = Alignment.center,
    this.startAngle = 0.0,
    this.endAngle = math.pi * 2,
    required List&lt;Color&gt; colors,
    List&lt;double&gt;? stops,
    this.tileMode = TileMode.clamp,
    GradientTransform? transform,
  }) : assert(center != null),
       assert(startAngle != null),
       assert(endAngle != null),
       assert(tileMode != null),
       super(colors: colors, stops: stops, transform: transform);
  </code></pre>
  <p><code>flutter</code> version:</p>
  <pre><code>Flutter 1.22.0-10.0.pre.153 • channel master • https://github.com/flutter/flutter.git
  Framework • revision 2e643651a9 (15 hours ago) • 2020-09-11 23:07:03 -0400
  Engine • revision 16b900b63e
  Tools • Dart 2.10.0 (build 2.10.0-117.0.dev)
  </code></pre>