WiFi config(): warning for legacy idioms (esp8266#9031 (comment))

Author: d-a-v

libraries/ESP8266WiFi/src/ESP8266WiFiSTA.h

@@ -49,6 +49,7 @@ class ESP8266WiFiSTAClass: public LwipIntf {
 
         // two and one parameter version. 2nd parameter is DNS like in Arduino
         // IPv4 only
+        [[deprecated("It is discouraged to use this 1 or 2 parameters network configuration legacy function config(ip[,dns]) because it sets the router (and ommited dns) to an arbitrary address")]]
         bool config(IPAddress local_ip, IPAddress dns = INADDR_ANY);
 
         bool setDNS(IPAddress dns1, IPAddress dns2 = INADDR_ANY);