build(deps): bump ws from 8.20.1 to 8.21.0 in /services/socket-mode

Bumps [ws](https://github.com/websockets/ws) from 8.20.1 to 8.21.0.
- [Release notes](https://github.com/websockets/ws/releases)
- [Commits](https://github.com/websockets/ws/compare/8.20.1...8.21.0)

---
updated-dependencies:
- dependency-name: ws
  dependency-version: 8.21.0
  dependency-type: indirect
...

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

services/socket-mode/package-lock.json

@@ -1182,9 +1182,9 @@
       "license": "MIT"
     },
     "node_modules/ws": {
-      "version": "8.20.1",
-      "resolved": "https://registry.npmjs.org/ws/-/ws-8.20.1.tgz",
-      "integrity": "sha512-It4dO0K5v//JtTXuPkfEOaI3uUN87iYPnqo/ZzqCoG3g8uhA66QUMs/SrM0YK7/NAu+r4LMh/9dq2A7k+rHs+w==",
+      "version": "8.21.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.21.0.tgz",
+      "integrity": "sha512-Vsp28b7DRcimFQvrqu2Wek3z1iYxDCWqHYB8Qsnk/S4RfaCQzPGPyBNuVjJV3cd6UiKtUtp6sNM77gWvzcCH+g==",
       "license": "MIT",
       "engines": {
         "node": ">=10.0.0"