Keep stats-lite at version 1 to avoid using ES6 features

Once we are using Node 4+, we can upgrade. See
ttps://www.npmjs.com/package/stats-lite

package.json

@@ -56,7 +56,7 @@
     "pelias-query": "^5.0.0",
     "pelias-schema": "2.0.0",
     "pelias-suggester-pipeline": "2.0.4",
-    "stats-lite": "^2.0.0",
+    "stats-lite": "1.0.3",
     "through2": "2.0.1"
   },
   "devDependencies": {