Update dependency flex_color_scheme to v8 (#1365)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

demo_app/pubspec.lock

@@ -234,18 +234,18 @@ packages:
     dependency: "direct main"
     description:
       name: flex_color_scheme
-      sha256: "32914024a4f404d90ff449f58d279191675b28e7c08824046baf06826e99d984"
+      sha256: "03fd5e68eff346a042026577f54be0cd4507e565cd86390b12c0aca1c5d6cb0b"
       url: "https://pub.dev"
     source: hosted
-    version: "7.3.1"
+    version: "8.0.0"
   flex_seed_scheme:
     dependency: transitive
     description:
       name: flex_seed_scheme
-      sha256: "4cee2f1d07259f77e8b36f4ec5f35499d19e74e17c7dce5b819554914082bc01"
+      sha256: "7639d2c86268eff84a909026eb169f008064af0fb3696a651b24b0fa24a40334"
       url: "https://pub.dev"
     source: hosted
-    version: "1.5.0"
+    version: "3.4.1"
   flutter:
     dependency: "direct main"
     description: flutter

demo_app/pubspec.yaml

@@ -9,7 +9,7 @@ environment:
 
 dependencies:
   carousel_slider: ^5.0.0
-  flex_color_scheme: ^7.3.1
+  flex_color_scheme: ^8.0.0
   flutter:
     sdk: flutter
   flutter_widget_from_html: any