ESP8266 Add ESP8266WiFi library requirement

Author: OttoWinter

library.json

@@ -30,6 +30,10 @@
  {
  "name": "Hash",
  "platforms": "espressif8266"
+ },
+ {
+ "name": "ESP8266WiFi",
+ "platforms": "espressif8266"
  }
  ]
 }