docs: add geo-json playground

<template>

  <l-map ref="map" v-model:zoom="zoom" :center="[47.41322, -1.219482]">

    <l-tile-layer

      url="https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png"

      layer-type="base"

      name="OpenStreetMap"

    ></l-tile-layer>

    <l-geo-json :geojson="geojson"></l-geo-json>

  </l-map>

</template>

<script>

import { LMap, LTileLayer, LGeoJson } from "./../../components";

export default {

  components: {

    LMap,

    LTileLayer,

    LGeoJson,

  },

  data() {

    return {

      zoom: 8,

      geojson: null,

    };

  },

  async created() {

    const response = await fetch(

      "https://rawgit.com/gregoiredavid/france-geojson/master/regions/pays-de-la-loire/communes-pays-de-la-loire.geojson"

    );

    this.geojson = await response.json();

  },

};

</script>

<style></style>