Trivial tab to space fix

Author: earlephilhower

cores/esp8266/IPAddress.h

@@ -136,7 +136,7 @@ class IPAddress: public Printable {
         // Overloaded copy operators to allow initialisation of IPAddress objects from other types
         IPAddress& operator=(const uint8_t *address);
         IPAddress& operator=(uint32_t address);
-	IPAddress& operator=(const IPAddress&) = default;
+        IPAddress& operator=(const IPAddress&) = default;
 
         virtual size_t printTo(Print& p) const;
         String toString() const;