py/persistentcode: Bump .mpy version number to version 3.

The binary and unary ops have changed bytecode encoding.

py/persistentcode.c

@@ -39,7 +39,7 @@
 #include "py/smallint.h"
 
 // The current version of .mpy files
-#define MPY_VERSION (2)
+#define MPY_VERSION (3)
 
 // The feature flags byte encodes the compile-time config options that
 // affect the generate bytecode.

tools/mpy-tool.py

@@ -57,7 +57,7 @@ class FreezeError(Exception):
         return 'error while freezing %s: %s' % (self.rawcode.source_file, self.msg)
 
 class Config:
-    MPY_VERSION = 2
+    MPY_VERSION = 3
     MICROPY_LONGINT_IMPL_NONE = 0
     MICROPY_LONGINT_IMPL_LONGLONG = 1
     MICROPY_LONGINT_IMPL_MPZ = 2