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>

tools/mpy-tool.py

@@ -88,7 +88,7 @@ class FreezeError(Exception):
 
 class Config:
     MPY_VERSION = 6
-    MPY_SUB_VERSION = 2
+    MPY_SUB_VERSION = 3
     MICROPY_LONGINT_IMPL_NONE = 0
     MICROPY_LONGINT_IMPL_LONGLONG = 1
     MICROPY_LONGINT_IMPL_MPZ = 2