Add Polo to "made with" page

Signed-off-by: Manuel Rego Casasnovas <rego@igalia.com>

Author: mrego

_data/madewith.json

@@ -75,6 +75,12 @@
                 "link": "https://lightpanda.io/",
                 "description": "A headless web browser that uses html5ever for parsing"
             },
+            {
+                "key": "polo",
+                "name": "Polo",
+                "link": "https://github.com/Ranrar/Marco/tree/servo",
+                "description": "A lightweight GTK4 markdown viewer using Servo for fast HTML rendering of parsed markdown documents"
+            },
             {
                 "key": "wry-backend",
                 "name": "Wry Backend",