Bump ws from 8.18.0 to 8.21.0

Bumps [ws](https://github.com/websockets/ws) from 8.18.0 to 8.21.0.
- [Release notes](https://github.com/websockets/ws/releases)
- [Commits](websockets/ws@8.18.0...8.21.0)

---
updated-dependencies:
- dependency-name: ws
  dependency-version: 8.21.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

package.json

@@ -48,7 +48,7 @@
     "tmp": "0.2.4",
     "tree-kill": "1.2.2",
     "update-notifier-cjs": "5.1.7",
-    "ws": "8.18.0"
+    "ws": "8.21.0"
   },
   "devDependencies": {
     "@architect/eslint-config": "~3.0.0",