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

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-Y18N-1021887

Author: snyk-bot

package-lock.json

@@ -46,7 +46,7 @@
     "node-cache": "^5.1.0",
     "strip-ansi": "^6.0.0",
     "yargonaut": "^1.1.4",
-    "yargs": "15.3.1"
+    "yargs": "16.0.0"
   },
   "devDependencies": {
     "eslint": "^6.8.0",