use fields instead of __match_args__ (#286)
* use fields instead of __match_args__
* Update python/openvino_tokenizers/utils.py
* Update tests/tokenizers_test.py
* Update python/openvino_tokenizers/convert_tokenizer.py
* Update tokenizers_test.py
* Update python/openvino_tokenizers/utils.py
* add import for fields
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Co-authored-by: Andrei Kochin <andrei.kochin@intel.com>
