Bump discord.js from 14.20.0 to 14.21.0

Bumps [discord.js](https://github.com/discordjs/discord.js/tree/HEAD/packages/discord.js) from 14.20.0 to 14.21.0.
- [Release notes](https://github.com/discordjs/discord.js/releases)
- [Changelog](https://github.com/discordjs/discord.js/blob/14.21.0/packages/discord.js/CHANGELOG.md)
- [Commits](https://github.com/discordjs/discord.js/commits/14.21.0/packages/discord.js)

---
updated-dependencies:
- dependency-name: discord.js
  dependency-version: 14.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -21,7 +21,7 @@
   "dependencies": {
     "@discordjs/opus": "^0.10.0",
     "discord-webhook-node": "^1.1.8",
-    "discord.js": "^14.20.0",
+    "discord.js": "^14.21.0",
     "dotenv": "^16.5.0",
     "firebase": "^11.9.1",
     "firebase-admin": "^13.4.0",