Use preferred tile.openstreetmap.org URL

Author: danieldegroot2

web/map_style/style.json

@@ -9,9 +9,7 @@
     "raster-tiles": {
       "type": "raster",
       "tiles": [
-        "https://a.tile.openstreetmap.org/{z}/{x}/{y}.png",
-        "https://b.tile.openstreetmap.org/{z}/{x}/{y}.png",
-        "https://c.tile.openstreetmap.org/{z}/{x}/{y}.png"
+        "https://tile.openstreetmap.org/{z}/{x}/{y}.png"
       ],
       "tileSize": 256,
       "maxzoom": 19,