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

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-VALIDATOR-13395830

Author: snyk-io[bot]

package-lock.json

@@ -46,7 +46,7 @@
     "stream-buffers": "^3.0.1",
     "tap": "^11.1.3",
     "typeorm": "^0.2.24",
-    "validator": "^13.5.2"
+    "validator": "^13.15.20"
   },
   "devDependencies": {
     "browserify": "^13.1.1",