chore(Snyk): Security upgrade snyk from 1.509.0 to 1.518.0 (#12753)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-NETMASK-1089716

package.json

@@ -46,7 +46,7 @@
     "qz-tray": "^2.0.8",
     "redis": "^2.8.0",
     "showdown": "^1.9.1",
-    "snyk": "^1.465.0",
+    "snyk": "^1.518.0",
     "socket.io": "^2.4.0",
     "superagent": "^3.8.2",
     "touch": "^3.1.0",