Stop explicitly supporting Node 0.10 and 0.11
diff --git a/package.json b/package.json
index 8a5f13b..fe364d3 100644
--- a/package.json
+++ b/package.json
@@ -45,7 +45,7 @@
     "poisson-process": "^0.2.1"
   },
   "engines": {
-    "node": ">=0.10.13"
+    "node": ">=0.12.0"
   },
   "binary": {
     "module_name": "grpc_node",