Updates pymorphy2 to pymorphy3

[ThHuberResearch]

The lexical_density function does not run in Python versions more recent than 3.10. This is because of an issue in the pymorphy2 package, which is used here. See this Stack Overflow answer for details - it seems like it is using a function that has been deprecated since Python 3.0, but which was only removed in Python 3.11.

Additionally pymorphy2 is abandoned: See here.
This pull request updates the code to use pymorphy3, which is the succcessor, still being maintained (as far as I can tell) and which fixes the issue of the lexical_density function from linguaf to not work under Python 3.11 (and most likely more recent versions as well, though I only tried it on 3.11).
The tests run without any issues.

Example demonstrating the issue (using Python 3.11):

from linguaf import lexical_diversity as ld


docs = ['This is document 1.', 'This is document 2.']
print(ld.lexical_density(docs))

With pymorphy2 the above code produces the following error:

Traceback (most recent call last):
  File "/home/thomas/PycharmProjects/LinguaF/debug.py", line 5, in <module>
    print(ld.lexical_density(docs))
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/linguaf/lexical_diversity.py", line 22, in lexical_density
    lex_items = get_lexical_items(documents=documents, remove_stopwords=remove_stopwords, lang=lang)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/linguaf/descriptive_statistics.py", line 363, in get_lexical_items
    morph = pymorphy2.MorphAnalyzer()
            ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/.venvLocal/lib/python3.11/site-packages/pymorphy2/analyzer.py", line 224, in __init__
    self._init_units(units)
  File "/home/thomas/PycharmProjects/LinguaF/.venvLocal/lib/python3.11/site-packages/pymorphy2/analyzer.py", line 235, in _init_units
    self._units.append((self._bound_unit(unit), False))
                        ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/.venvLocal/lib/python3.11/site-packages/pymorphy2/analyzer.py", line 246, in _bound_unit
    unit = unit.clone()
           ^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/.venvLocal/lib/python3.11/site-packages/pymorphy2/units/base.py", line 35, in clone
    return self.__class__(**self._get_params())
                            ^^^^^^^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/.venvLocal/lib/python3.11/site-packages/pymorphy2/units/base.py", line 76, in _get_params
    (key, getattr(self, key, None)) for key in self._get_param_names()
                                               ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/thomas/PycharmProjects/LinguaF/.venvLocal/lib/python3.11/site-packages/pymorphy2/units/base.py", line 70, in _get_param_names
    args, varargs, kw, default = inspect.getargspec(cls.__init__)
                                 ^^^^^^^^^^^^^^^^^^
AttributeError: module 'inspect' has no attribute 'getargspec'. Did you mean: 'getargs'?

The same code, but using pymorphy3:

/home/thomas/PycharmProjects/LinguaF/.venvLocal/bin/python /home/thomas/PycharmProjects/LinguaF/debug.py 
50.0

Process finished with exit code 0

[Perevalov]

Thanks @ThHuberSG I'll test it soon and approve if everything goes well

[Perevalov]

Looks good. Tested it locally.