The ESP8266 version of the mDNS library expected service name and protocol without leading '_' (underscore). The ESP32 version expected service name and protocol with leading '_' (underscore).
This small change makes the ESP32 version compatible with the ESP8266 version and keeps backward compatible with existing code by accepting service name and protocol either with or without leading '_' (underscore).
* Update mDNS and LEDC
* update toolchain
* Update IDF to 1c3dd23
* Advertise the board variant for Arduino OTA
* Add generic variant definition for mDNS
