Opens a file for tracking the time of the last version check

def timestamp_file():
    """Opens a file for tracking the time of the last version check"""
    config_dir = os.path.join(
        os.path.expanduser("~"), BaseGlobalConfig.config_local_dir
    )

    if not os.path.exists(config_dir):
        os.mkdir(config_dir)

    timestamp_file = os.path.join(config_dir, "cumulus_timestamp")

    try:
        with open(timestamp_file, "r+") as f:
            yield f
    except IOError:  # file does not exist
        with open(timestamp_file, "w+") as f:
            yield f