docs: fix grafana typo

Author: savvar9991

README.md

@@ -62,7 +62,7 @@ Browse to your webapp and open the DevTools, you should see a "libp2p" tab towar
   - It's quite rough
 3. Graphs
   - We don't do much with the collected metrics yet. It would be nice to use Chart.js or similar to show some useful graphs
-  - Bonus points for letting the user define their own graphs a la Graphana/Prometheus
+  - Bonus points for letting the user define their own graphs a la Grafana/Prometheus
   - More bonus points for being able to export/import graph configs
 4. Dynamic panels
   - We should be able to inspect the libp2p node's configured services (or protocols?) and, for example, only show a DHT tab if the DHT is configured