dependencies: bump ws from 8.16.0 to 8.18.0

Bumps [ws](https://github.com/websockets/ws) from 8.16.0 to 8.18.0.
- [Release notes](https://github.com/websockets/ws/releases)
- [Commits](websockets/ws@8.16.0...8.18.0)

---
updated-dependencies:
- dependency-name: ws
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -56,7 +56,7 @@
   "homepage": "https://github.com/vansergen/poloniex-node-api#readme",
   "dependencies": {
     "rpc-request": "^7.1.9",
-    "ws": "^8.16.0"
+    "ws": "^8.18.0"
   },
   "peerDependencies": {
     "@types/ws": "^8.5.4"