Update engine-handlebars dependencies

Updated dependencies to reduce critical npm audit error

Author: Josef Bredreck

packages/engine-handlebars/package.json

@@ -6,7 +6,7 @@
   "dependencies": {
     "fs-extra": "0.30.0",
     "glob": "7.0.0",
-    "handlebars": "4.0.5"
+    "handlebars": "4.2.0"
   },
   "keywords": [
     "Pattern Lab",