msgpack: add lru_cache for init_msgpack_extensions

Author: Артем Ветошкин

tarantool/msgpack_ext/extensions.py

@@ -40,6 +40,7 @@ class Extension(namedtuple("Extension", "decode encode type")):
 TARANTOOL_DECIMAL_MAX_DIGITS_V35 = 76
 
 
+@functools.lru_cache(maxsize=None)
 def init_msgpack_extensions(tarantool_version=None):
     """
     Initialize MessagePack extension type handlers.