Use Diagnosticable instead of DiagnosticableMixin (#166)
Now that Diagnosticable in Flutter's stable release is a mixin, use that instead, since DiagnosticableMixin will be going away. The two mixin classes are identical, so there should be no change in functionality.
In anticipation of flutter/flutter#50498
diff --git a/packages/palette_generator/lib/palette_generator.dart b/packages/palette_generator/lib/palette_generator.dart
index 0486c9d..6cc1df3 100644
--- a/packages/palette_generator/lib/palette_generator.dart
+++ b/packages/palette_generator/lib/palette_generator.dart
@@ -59,7 +59,7 @@
/// * [PaletteTarget], to be able to create your own target color types.
/// * [PaletteFilter], a function signature for filtering the allowed colors
/// in the palette.
-class PaletteGenerator with DiagnosticableMixin {
+class PaletteGenerator with Diagnosticable {
/// Create a [PaletteGenerator] from a set of paletteColors and targets.
///
/// The usual way to create a [PaletteGenerator] is to use the asynchronous
@@ -369,7 +369,7 @@
/// See also:
///
/// * [PaletteGenerator], a class for selecting color palettes from images.
-class PaletteTarget with DiagnosticableMixin {
+class PaletteTarget with Diagnosticable {
/// Creates a [PaletteTarget] for custom palette selection.
///
/// None of the arguments can be null.
@@ -597,7 +597,7 @@
/// See also:
///
/// * [PaletteGenerator], a class for selecting color palettes from images.
-class PaletteColor with DiagnosticableMixin {
+class PaletteColor with Diagnosticable {
/// Generate a [PaletteColor].
///
/// The `color` and `population` parameters must not be null.
