Version bump to 6.4.0, 2021 initial build

lib/SCSI2SD/src/firmware/config.c

@@ -36,7 +36,7 @@
 
 #include <string.h>
 
-static const uint16_t FIRMWARE_VERSION = 0x0632;
+static const uint16_t FIRMWARE_VERSION = 0x0640;
 
 // Optional static config
 extern uint8_t* __fixed_config;