Fix lint error in playground

        <l-circle :lat-lng="[35.865, 12.865]" :radius="10000" color="green" />

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

      </l-map>

      <button @click="changeIcon">New kitten icon</button>

      <label for="attributionPrefix">Attribution prefix:</label>