fix: add node 18 + 20 compatibility

server/index.js

@@ -11,7 +11,7 @@ const { gte } = require('semver')
 // ----------------------------------------
 // Check Node.js version
 // ----------------------------------------
-if (gte(process.version, '18.0.0')) {
+if (gte(process.version, '21.0.0')) {
   console.error('You\'re using an unsupported Node.js version. Please read the requirements.')
   process.exit(1)
 }