Update utils.dart

pkgs/yaml_edit/lib/src/utils.dart

diff --git a/pkgs/yaml_edit/lib/src/utils.dart b/pkgs/yaml_edit/lib/src/utils.dart
index ef85526..7a27fd4 100644
--- a/pkgs/yaml_edit/lib/src/utils.dart
+++ b/pkgs/yaml_edit/lib/src/utils.dart
@@ -41,7 +41,7 @@
 
     // [string] should also not contain the `[`, `]`, `,`, `{` and `}` indicator
     // characters.
-    return string.contains(RegExp(r'\{|\[|\]|\}|,'));
+    return string.contains(RegExp(r'[{}\[\],]'));
   } catch (e) {
     /// This catch statement catches [ArgumentError] in `loadYamlNode` when
     /// a string can be interpreted as a URI tag, but catches for other