ci: Run Pylint strictly on new files, softly on history

[ko3n1g]

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[github-actions]

Your code was analyzed with PyLint. The following annotations have been identified:

************* Module nemo.core.classes.dataset2
nemo/core/classes/dataset2.py:102:0: C0115: Missing class docstring (missing-class-docstring)
************* Module nemo.core.classes.dataset
nemo/core/classes/dataset.py:102:0: C0115: Missing class docstring (missing-class-docstring)
************* Module nemo.core.classes.exportable
nemo/core/classes/exportable.py:41:0: C0301: Line too long (120/119) (line-too-long)
nemo/core/classes/exportable.py:81:0: C0301: Line too long (121/119) (line-too-long)
nemo/core/classes/exportable.py:102:0: C0301: Line too long (120/119) (line-too-long)
nemo/core/classes/exportable.py:53:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/core/classes/exportable.py:57:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/core/classes/exportable.py:320:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/core/classes/exportable.py:324:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/core/classes/exportable.py:328:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/core/classes/exportable.py:332:4: C0116: Missing function or method docstring (missing-function-docstring)
nemo/core/classes/exportable.py:335:4: C0116: Missing function or method docstring (missing-function-docstring)

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