remove stable from Travis config
diff --git a/pkgs/json_rpc_2/.travis.yml b/pkgs/json_rpc_2/.travis.yml
index 63f5e5e..7dee3cc 100644
--- a/pkgs/json_rpc_2/.travis.yml
+++ b/pkgs/json_rpc_2/.travis.yml
@@ -2,8 +2,6 @@
 
 dart:
   - dev
-  - stable
-
 dart_task:
   - test
   - dartanalyzer