Compatibility issue with Python 3.7

[AiOO]

Since the typing module in Python 3.7 doesn't have TupleMeta class, AttributeError occurs by below line . To support Python 3.7 it should be fixed.

nirum-python/nirum/deserialize.py

Line 203 in 1721295

elif type(cls) is typing.TupleMeta:

relative commit: python/cpython@d911e40#diff-015978a768b517a38abbc0ecdea87f5a

[kanghyojun]

However, with the higher version of Nirum compiler, deserialize_meta dosen't used anymore. So we should fix compiler code https://github.com/nirum-lang/nirum/blob/0.5-maintenance/src/Nirum/Targets/Python.hs

[kanghyojun]

Since nirum-lang/nirum#278 was merged, deserialized_meta was deprecated and typing.TupleMeta wasn't used anymore. So I think that there are no bugs if you use the latest version of Nirum compiler. Thanks for your reporting :)