fix(deps): update dependency proj4 to v2.20.0

Author: renovate[bot]

package.json

@@ -57,7 +57,7 @@
     "ol": "^10.3.1",
     "ol-contextmenu": "^5.5.0",
     "ol-mapbox-style": "^12.3.5",
-    "proj4": "2.15.0",
+    "proj4": "2.20.0",
     "sortablejs": "1.15.3",
     "typescript": "^5.3.3",
     "whatwg-fetch": "3.6.20",