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.

src/components/_DataProperty.tsx

@@ -1,6 +1,6 @@
 import React from 'react'
 import {mdiFunctionVariant, mdiTableRowPlusAfter} from '@mdi/js';
-import {latest} from '@maplibre/maplibre-gl-style-spec'
+import latest from '@maplibre/maplibre-gl-style-spec/dist/latest.json'
 
 import InputButton from './InputButton'
 import InputSpec from './InputSpec'
@@ -302,7 +302,7 @@ export default class DataProperty extends React.Component<DataPropertyProps, Dat
               <div className="maputnik-data-spec-property-input">
                 <InputSpec
                   fieldName={"base"}
-                  fieldSpec={latest.function.base}
+                  fieldSpec={latest.function.base as typeof latest.function.base & { type: "number" }}
                   value={this.props.value?.base}
                   onChange={(_, newValue) => this.changeBase(newValue as number)}
                 />