fix #187

Author: ladyada

boards.txt

@@ -262,7 +262,7 @@ adafruit_trinket_m0.build.variant_system_lib=
 adafruit_trinket_m0.build.vid=0x239A
 adafruit_trinket_m0.build.pid=0x801E
 adafruit_trinket_m0.bootloader.tool=openocd
-adafruit_trinket_m0.bootloader.file=trinketM0/bootloader-trinket_m0-v2.0.0-adafruit.5.bin
+adafruit_trinket_m0.bootloader.file=trinketm0/bootloader-trinket_m0-v2.0.0-adafruit.5.bin
 adafruit_trinket_m0.menu.usbstack.arduino=Arduino
 adafruit_trinket_m0.menu.usbstack.tinyusb=TinyUSB
 adafruit_trinket_m0.menu.usbstack.tinyusb.build.flags.usbstack=-DUSE_TINYUSB