Slightly loosen dependencies
diff --git a/templates/package.json.template b/templates/package.json.template
index 5c2acf4..d50b1e2 100644
--- a/templates/package.json.template
+++ b/templates/package.json.template
@@ -33,7 +33,7 @@
       "protobufjs": "^4.0.0"
     },
     "devDependencies": {
-      "async": "^1.5.1",
+      "async": "^1.5.0",
       "google-auth-library": "^0.9.2",
       "istanbul": "^0.3.21",
       "jsdoc": "^3.3.2",