promote arg of flashErase() from byte to int

src/Nano33BLEflash.cpp

@@ -36,7 +36,7 @@ void flashMode(_flashModeEnum mode)
 }
 
 //int Nano33BLEflash::erase(byte page)
-int flashErasePage(byte page)
+int flashErasePage(int page)
 {
   /*
    * Function erases the page given by the input parameter page.

src/Nano33BLEflash.h

@@ -59,7 +59,7 @@ const unsigned int flashBytesPerWord  = 4;
 const unsigned int flashNumberOfPages = NRF_FICR->CODESIZE;      //  256 pages
 
 void flashMode(_flashModeEnum mode);
-int flashErasePage(byte page);
+int flashErasePage(int page);
 void _wait4flash2Bready(void);
 
 /*