chore: update dependency validator to ^13.15.20 [security]

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -68,7 +68,7 @@
     "strong-error-handler": "^5.0.24",
     "tslib": "^2.8.1",
     "type-is": "^2.0.1",
-    "validator": "^13.15.15"
+    "validator": "^13.15.20"
   },
   "devDependencies": {
     "@loopback/build": "^12.0.5",