Upgrade node from v6 to v8 (backwards compatible)

Author: jotto

serverless.yml

@@ -9,7 +9,7 @@ service: Lambda-Edge-Prerendercloud
 
 provider:
   name: aws
-  runtime: nodejs6.10
+  runtime: nodejs8.10
   region: us-east-1
   memorySize: 128
   role: LambdaEdgeRole