List out the boards for our client

def main(api_key, token):
    """List out the boards for our client"""
    trello_client = TrelloClient(
        api_key=api_key,
        token=token,
    )
    print('Boards')
    print('-----')
    print('Name: Id')
    for board in trello_client.list_boards():
        print('{board.name}: {board.id}'.format(board=board))