fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-UNDICI-6252336
- https://snyk.io/vuln/SNYK-JS-UNDICI-6564963
- https://snyk.io/vuln/SNYK-JS-UNDICI-6564964

package.json

@@ -43,7 +43,7 @@
     "axios": "^1.6.8",
     "dayjs": "^1.11.6",
     "discord-tictactoe": "^4.0.0",
-    "discord.js": "^14.14.1",
+    "discord.js": "^14.15.1",
     "dotenv": "^16.0.1",
     "execa": "^6.1.0",
     "express": "^4.18.1",