esp_now_get_version() function

Get the version of ESPNOW. Currently, ESPNOW supports two versions: v1.0 and v2.0. The v2.0 devices are capable of receiving packets from both v2.0 and v1.0 devices. In contrast, v1.0 devices can only receive packets from other v1.0 devices. However, v1.0 devices can receive v2.0 packets if the packet length is less than or equal to ESP_NOW_MAX_IE_DATA_LEN. For packets exceeding this length, the v1.0 devices will either truncate the data to the first ESP_NOW_MAX_IE_DATA_LEN bytes or discard the packet entirely. For detailed behavior, please refer to the documentation corresponding to the specific IDF version.