Fetch leaflet providers from Leaflet.js.
get_providers(version_num = NULL)leaflet_providers object containing providers_version_num, providers_data,
providers_details_data, src
if (
interactive() &&
requireNamespace("V8", quietly = TRUE) &&
requireNamespace("jsonlite", quietly = TRUE)
) {
get_providers()
get_providers("1.8.0")
}