feat(doc): Add main description for release v2.0.0 in README
feat(doc): Add main description for release v2.0.0 in README

espressif/ESP8266_RTOS_SDK,espressif/ESP8266_RTOS_SDK,espressif/ESP8266_RTOS_SDK,espressif/ESP8266_RTOS_SDK,espressif/ESP8266_RTOS_SDK