devel/py-frozendict: limit supported python versions

Python 3.10:
/wrkdirs/usr/ports/devel/py-frozendict/work-py310/frozendict-2.0.6/frozendict/src/3_10/cpython_src/Include/Python.h:72:10: fatal error: 'pytime.h' file not found
#include "pytime.h"

Python 3.11:
cc: error: no such file or directory: '/wrkdirs/usr/ports/devel/py-frozendict/work-py311/frozendict-2.0.6/frozendict/src/3_11/cpython_src/Objects/dictobject.c'

Approved by: portmgr blanket