Fix BigTree_Btt002 build

platformio.ini

@@ -483,7 +483,7 @@ monitor_speed = 250000
 [env:BIGTREE_BTT002]
 platform = ststm32@5.4.3
 framework = arduino
-board = BigTree_BTT002
+board = BigTree_Btt002
 extra_scripts = pre:buildroot/share/PlatformIO/scripts/generic_create_variant.py
 build_flags = ${common.build_flags}
   -DUSBCON -DUSBD_USE_CDC -DUSBD_VID=0x0483 -DUSB_PRODUCT=\"STM32F407VE\"