Update pyproject.toml - replace output_formatting with output-formatting

[barseghyanartur]

closes #55290

Simply said, none of this would work (dependencies from output-formatting would not be installed):

pip install pandas[output-formatting]
pip install pandas[output_formatting]
pip install pandas[output-formatting,xml]

When being distributed, underscores are replaces with dashes. So, in the packaged PKG-INFO file you won't find spots of output_formatting, but only output-formatting:

Requires-Dist: lxml>=4.8.0; extra == "xml"
Requires-Dist: jinja2>=3.1.2; extra == "output-formatting"
Requires-Dist: tabulate>=0.8.10; extra == "output-formatting"

But on the same time, this:

Provides-Extra: output_formatting

This fix addresses that.

[mroeschke]

Thanks could you add a whatsnew note in 2.1.2.rst?

[barseghyanartur]

@mroeschke:

Done.

[mroeschke]

Could you also change the references in doc/source/getting_started/install.rst and .github/workflows/package-checks.yml?

[barseghyanartur]

@mroeschke:

Done.

[mroeschke]

Thanks @barseghyanartur