Update charts_flutter to 0.12.0 (#951)

experimental/web_dashboard/pubspec.lock

@@ -112,16 +112,14 @@ packages:
       name: charts_common
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.11.0"
+    version: "0.12.0"
   charts_flutter:
     dependency: "direct main"
     description:
-      path: charts_flutter
-      ref: "03c2aa67d12952e7f3cbba1d87646d96a9a7cdc4"
-      resolved-ref: "03c2aa67d12952e7f3cbba1d87646d96a9a7cdc4"
-      url: "git://github.com/google/charts.git"
-    source: git
-    version: "0.11.0"
+      name: charts_flutter
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.12.0"
   checked_yaml:
     dependency: transitive
     description:

experimental/web_dashboard/pubspec.yaml

@@ -15,13 +15,7 @@ dependencies:
   json_annotation: ^4.1.0
   provider: ^6.0.0
   uuid: ^3.0.0
-  # The published version of charts_flutter is not up to date with master:
-  # https://github.com/google/charts/issues/678
-  charts_flutter:
-    git:
-      url: git://github.com/google/charts.git
-      path: charts_flutter
-      ref: 03c2aa67d12952e7f3cbba1d87646d96a9a7cdc4
+  charts_flutter: ^0.12.0
 dev_dependencies:
   flutter_test:
     sdk: flutter