bump handlebars to 4.1.2 to fix vulnerability issue

Author: Sahat Yalkabov

package.json

@@ -26,7 +26,7 @@
   "dependencies": {
     "glob": "^7.1.3",
     "graceful-fs": "^4.1.2",
-    "handlebars": "^4.0.13",
+    "handlebars": "^4.1.2",
     "object.assign": "^4.1.0",
     "promise": "^8.0.2"
   },