list method
List the roles in this guild.
Implementation
Future<List<Role>> list() async {
final route = HttpRoute()
..guilds(id: guildId.toString())
..roles();
final request = BasicRequest(route);
final response = await client.httpHandler.executeSafe(request);
final roles = parseMany(response.jsonBody as List, parse);
roles.forEach(client.updateCacheWith);
return roles;
}