Fix documentation building

[StrikerRUS]

Pin Python version to 3.9 in docs generating workflow (default is 3.10) to avoid installing scipy from sources and the following error:

Processing dependencies for sklearn-contrib-lightning==0.6.2.dev0
Searching for scipy
Reading https://pypi.org/simple/scipy/
Downloading https://files.pythonhosted.org/packages/29/d2/151a54944b333e465f98804dced31dab1284f3c37b752b9cefa710b64681/scipy-1.8.0rc2.tar.gz#sha256=d73b13eb0452c178f946b4db60b27e400225df02e926609652ed67798054e77d
Best match: scipy 1.8.0rc2
Processing scipy-1.8.0rc2.tar.gz
Writing /tmp/easy_install-we9rlw9q/scipy-1.8.0rc2/setup.cfg
Running scipy-1.8.0rc2/setup.py -q bdist_egg --dist-dir /tmp/easy_install-we9rlw9q/scipy-1.8.0rc2/egg-dist-tmp-r9r7tpz2
/tmp/easy_install-we9rlw9q/scipy-1.8.0rc2/setup.py:481: UserWarning: Unrecognized setuptools command ('-q bdist_egg --dist-dir /tmp/easy_install-we9rlw9q/scipy-1.8.0rc2/egg-dist-tmp-r9r7tpz2'), proceeding with generating Cython sources and expanding templates
  warnings.warn("Unrecognized setuptools command ('{}'), proceeding with "
error: Setup script exited with 1
Error: 'pybind11' must be installed before running the build.

Also, update github-pages-deploy-action's version to fetch all recent bugfixes and security updates.

I've tested this PR - works fine: https://github.com/scikit-learn-contrib/lightning/runs/4637378443?check_suite_focus=true