Update package:vm_service to >=6.0.0 <14.0.0 (#2130)

pkgs/test_core/pubspec.yaml

diff --git a/pkgs/test_core/pubspec.yaml b/pkgs/test_core/pubspec.yaml
index d3132ac..6451c83 100644
--- a/pkgs/test_core/pubspec.yaml
+++ b/pkgs/test_core/pubspec.yaml
@@ -27,7 +27,7 @@
   stream_channel: ^2.1.0
   # Use an exact version until the test_api package is stable.
   test_api: 0.6.1
-  vm_service: ">=6.0.0 <13.0.0"
+  vm_service: ">=6.0.0 <14.0.0"
   yaml: ^3.0.0
 
 dev_dependencies: