validate call hook urls (#431)

package-lock.json

@@ -33,6 +33,7 @@
         "form-data": "^4.0.0",
         "helmet": "^7.1.0",
         "ibm-watson": "^9.0.1",
+        "is-valid-hostname": "^1.0.2",
         "jsonwebtoken": "^9.0.2",
         "mailgun.js": "^10.2.1",
         "microsoft-cognitiveservices-speech-sdk": "1.36.0",
@@ -8533,6 +8534,12 @@
       "resolved": "https://registry.npmjs.org/is-typedarray/-/is-typedarray-1.0.0.tgz",
       "integrity": "sha512-cyA56iCMHAh5CdzjJIa4aohJyeO1YbwLi3Jc35MmRU6poroFjIGZzUzupGiRPOjgHg9TLu43xbpwXk523fMxKA=="
     },
+    "node_modules/is-valid-hostname": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/is-valid-hostname/-/is-valid-hostname-1.0.2.tgz",
+      "integrity": "sha512-X/kiF3Xndj6WI7l/yLyzR7V1IbQd6L4S4cewSL0fRciemPmHbaXIKR2qtf+zseH+lbMG0vFp4HvCUe7amGZVhw==",
+      "license": "MIT"
+    },
     "node_modules/is-weakmap": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/is-weakmap/-/is-weakmap-2.0.2.tgz",