py/persistentcode: Bump .mpy sub-version to 6.3.

This is required because the .mpy native ABI was changed by the
introduction of `mp_proto_fun_t`, see commits:
- 416465d81e
- 5e3006f117
- e2ff00e811

And three `mp_binary` functions were added to `mp_fun_table` in
commit d2276f0d41.

Signed-off-by: Damien George <damien@micropython.org>

py/persistentcode.h

@@ -35,7 +35,7 @@
 // set) must also match MPY_SUB_VERSION. This allows 3 additional updates to
 // the native ABI per bytecode revision.
 #define MPY_VERSION 6
-#define MPY_SUB_VERSION 2
+#define MPY_SUB_VERSION 3
 
 // Macros to encode/decode sub-version to/from the feature byte. This replaces
 // the bits previously used to encode the flags (map caching and unicode)