Update charted to 0.4.8 and roll

packages/source_span/test/utils_test.dart

Index: packages/source_span/test/utils_test.dart
diff --git a/packages/source_span/test/utils_test.dart b/packages/source_span/test/utils_test.dart
index 5d973f58acf29578617cec0f40529602ecef0e1c..2a86cc070f77654450ca504fb779545eb9c4b996 100644
--- a/packages/source_span/test/utils_test.dart
+++ b/packages/source_span/test/utils_test.dart
@@ -45,11 +45,3 @@ main() {
     });
   });
 }
-
-_linearSearch(list, predicate) {
-  if (list.length == 0) return -1;
-  for (int i = 0; i < list.length; i++) {
-    if (predicate(list[i])) return i;
-  }
-  return list.length;
-}