Update MapLibre dependencies, add terrain editing (#859)

This PR aims at updating MapLibre dependencies.

The main goal of this update is to allow adding terrain specification to
the editor.
This requires version 4 of maplibre so currently it will use the
pre-release.

package.json

@@ -23,7 +23,7 @@
   "homepage": "https://github.com/maputnik/editor#readme",
   "dependencies": {
     "@mapbox/mapbox-gl-rtl-text": "^0.2.3",
-    "@maplibre/maplibre-gl-style-spec": "^17.0.1",
+    "@maplibre/maplibre-gl-style-spec": "^20.1.0",
     "@mdi/js": "^6.6.96",
     "@mdi/react": "^1.5.0",
     "@typescript-eslint/eslint-plugin": "^6.16.0",
@@ -46,7 +46,7 @@
     "lodash.isequal": "^4.5.0",
     "lodash.throttle": "^4.1.1",
     "mapbox-gl-inspect": "^1.3.1",
-    "maplibre-gl": "^2.4.0",
+    "maplibre-gl": "^4.0.0-pre.4",
     "maputnik-design": "github:maputnik/design#172b06c",
     "ol": "^6.14.1",
     "ol-mapbox-style": "^7.1.1",