Use latest pkg:json_serializable
diff --git a/pkgs/timing/pubspec.yaml b/pkgs/timing/pubspec.yaml
index 25d8124..efda7ce 100644
--- a/pkgs/timing/pubspec.yaml
+++ b/pkgs/timing/pubspec.yaml
@@ -12,6 +12,6 @@
 
 dev_dependencies:
   build_runner: ^1.0.0
-  json_serializable: ^1.0.0
+  json_serializable: ^2.0.0
   pedantic: ^1.1.0
   test: ^1.0.0