pullup for bootloader-key, now the bootloader exits if the key is released

bootloader/bootloaderconfig.h

@@ -140,6 +140,8 @@ static inline void bootLoaderInit(void) {
     // and later look for column 7
     DDRA  = 0x00;
     PORTA = 0xff;
+    DDRB &= ~(1 << PB7);
+    PORTB |= (1 << PB7);
     DDRC  = (1 << DDC2);
     PORTC = ~(1 << PINC2);
 }