v2.7.4

### Releases v2.7.4

1. Sync with v2.7.4 of original [**SinricPro library**](https://github.com/sinricpro/esp8266-esp32-sdk). Check [Change Log](https://github.com/khoih-prog/SinricPro_Generic/blob/master/changelog.md) for more details.
2. Add examples and support to WIO Terminal, and in general boards with **Realtek RTL8720DN WiFi** using [**Seeed_Arduino_rpcWiFi**](https://github.com/Seeed-Studio/Seeed_Arduino_rpcWiFi) and [**Seeed_Arduino_rpcUnified**](https://github.com/khoih-prog/Seeed_Arduino_rpcUnified) libraries. This RTL8720DN supports Dual-Band 2.4GHz / 5GHz Wi-Fi (802.11 a/b/g/n) as well as BLE/BLE 5.0. To be used with [`WebSockets_Generic v2.3.2+`](https://github.com/khoih-prog/WebSockets_Generic).