Update dependency ejs to v3

Author: renovate-bot

package.json

@@ -25,7 +25,7 @@
     "body-parser": "^1.17.1",
     "cookie-parser": "^1.4.3",
     "cookieparser": "^0.1.0",
-    "ejs": "^2.5.6",
+    "ejs": "^3.0.0",
     "events": "^1.1.1",
     "express": "^4.15.2",
     "express-flash-2": "^1.0.1",