fix: package.json & package-lock.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-HANDLEBARS-567742

Author: snyk-bot

package.json

@@ -157,7 +157,7 @@
         "colors": "~1.3.3",
         "fluture": "~11.0.3",
         "fluture-sanctuary-types": "~4.1.1",
-        "handlebars": "~4.5.3",
+        "handlebars": "~4.6.0",
         "immer": "~4.0.2",
         "inquirer": "~6.2.1",
         "lodash": "~4.17.15",