fix: configure express to know about Cloud Run's proxy (#3586)

* fix: configure express to know about Cloud Run's proxy

* fix: lint

---------

Co-authored-by: Patti Shin <pattishin@users.noreply.github.com>

Author: glasnt

run/filesystem/index.js

@@ -37,6 +37,9 @@ const limit = rateLimit({
 app.use(limit);
 app.use(mntDir, express.static(mntDir));
 
+// configure express to know about Cloud Run's proxy
+app.set('trust proxy', 1);
+
 app.listen(port, () => {
   console.log(`Listening on port ${port}`);
 });