Add examples/ and docs/requirements.txt to source distribution

[musicinmybrain]

https://github.com/mechmotum/cyipopt/issues/237#issuecomment-1826793291

This PR seems to be effective for python3 setup.py sdist but not for python3 -m build.

[moorepants]

This may be better:

include setup.py
include AUTHORS
include LICENSE
include CHANGELOG.rst
include README.rst
recursive-include cyipopt *.py *.pyx *.pxd
recursive-include ipopt *.py
recursive-include tests *.py
recursive-include docs Makefile *.bat *.rst *.py requirements.txt
recursive-include examples *.py
exclude cyipopt/tests/unit/test_scipy_ipopt_from_scipy.py
prune include*
prune lib*

[musicinmybrain]

You’re absolutely right that I was misusing recursive-include. Thanks.

Also, I typo’ed .txt.

I’ve force-pushed a new pair of commits that makes much more sense, and which appear to work correctly with both python3 setup.py sdist and python3 -m build.

[moorepants]

I'm good with this. Thanks!