Parse RTC_MIN_PORT and RTC_MAX_PORT

app.js

@@ -67,8 +67,8 @@ const peers = io.of('/');
 const createWorker = async () => {
   try {
     worker = await mediasoup.createWorker({
-      rtcMinPort: process.env.RTC_MIN_PORT,
-      rtcMaxPort: process.env.RTC_MAX_PORT,
+      rtcMinPort: parseInt(process.env.RTC_MIN_PORT),
+      rtcMaxPort: parseInt(process.env.RTC_MAX_PORT),
     })
     console.log(`[createWorker] worker pid ${worker.pid}`);