Bumps minimum engine to 4.5 (#2733)

Author: flovilmart

.travis.yml

@@ -1,6 +1,6 @@
 language: node_js
 node_js:
-- '4.3'
+- '4.5'
 - '6.1'
 services:
   - postgresql

package.json

@@ -73,7 +73,7 @@
     "prepublish": "npm run build"
   },
   "engines": {
-    "node": ">=4.3"
+    "node": ">=4.5"
   },
   "bin": {
     "parse-server": "./bin/parse-server"