Update index.js

fix: should pick host name from the env file for the HTTPS cert.

Author: arkokoley

src/index.js

@@ -594,8 +594,8 @@ app.get('/logout', (req, res) => {
 
 https
     .createServer({
-        key: fs.readFileSync(path.join(__dirname, '../threads-sample.meta-key.pem')),
-        cert: fs.readFileSync(path.join(__dirname, '../threads-sample.meta.pem')),
+        key: fs.readFileSync(path.join(__dirname, '../'+ HOST +'-key.pem')),
+        cert: fs.readFileSync(path.join(__dirname, '../'+ HOST +'.pem')),
     }, app)
     .listen(PORT, HOST, (err) => {
         if (err) {