adds esp8266-style hostname setting (espressif#4938)

a little step to make esp8266 code compile without changes under esp32

Author: holgerlembke

libraries/WiFi/src/WiFiSTA.h

@@ -74,6 +74,7 @@ class WiFiSTAClass
 
     const char * getHostname();
     bool setHostname(const char * hostname);
+    bool hostname(const String& aHostname) { return setHostname(aHostname.c_str()); }
 
     // STA WiFi info
     static wl_status_t status();