fix(package): update pm2 to version 4.1.0

Closes #24

Author: greenkeeper[bot]

package.json

@@ -14,7 +14,7 @@
 	"dependencies": {
 		"eslint": "^5.0.0",
 		"mongodb": "^3.0.10",
-		"pm2": "^3.0.0"
+		"pm2": "^4.1.0"
 	},
 	"devDependencies": {
 		"chai": "^4.1.2",