Add twine check to CI

[kmike]

It'd be nice to do https://twine.readthedocs.io/en/stable/#twine-check on CI, to ensure our changes don't break pypi rendering.

[armujahid]

How to create dist for twine check? I have tried python setup.py build and python setup.py sdist. 2nd one is creating dist with Scrapy-2.6.2.tar.gz

Running twine check dist throws this error

Checking dist: ERROR    InvalidDistribution: Unknown distribution format: 'dist'                                                                                                                      

Looks like I am doing something wrong
Related: #5648

Update #1:
I created dist using python setup.py sdist bdist_wheel but I am getting same error with twine check. dist directory has Scrapy-2.6.2-py2.py3-none-any.whl and Scrapy-2.6.2.tar.gz

[armujahid]

I think this is the correct way to run twine check. Correct me If I am wrong.

rm -rf dist
python setup.py sdist bdist_wheel
twine check dist/*

Update: Correct steps to create distribution are also mentioned here in publish workflow
Now I think I just need to add a new check in checks.yml