Update deprecated 'description-file' in setup.cfg

[xmedr]

Can't install docx2txt with Setuptools verision>=78

See Setuptools changelog :

"Setuptools no longer accepts options containing uppercase or dash characters in setup.cfg. Please ensure to write the options in setup.cfg using the lower_snake_case convention (e.g. Name => name, install-requires => install_requires). This is a follow-up on deprecations introduced in v54.1.0 (see pypa/setuptools#1608) and v54.1.1 (see pypa/setuptools#2592)."

[gregoryjflaherty]

Same issue here

[logan-markewich]

@ankushshah89 are you still around to help release a small patch for this? I can open a PR too, but I think you'll still need to merge it

[MykolaRomaniv]

For additional context you can look here
pypa/setuptools#4910

[michael-crowdbotics]

Same here. This is currently preventing our build from completing