map minutes to numbers

src/departures-router.mjs

@@ -27,6 +27,7 @@ departuresRouter.get('/departures', (req, res) => {
         .flatMap((stop) => {
           return stop.departures.flatMap((d) => d.next);
         })
+        .map(Number)
         .sort();
 
       return res.json(minutes);