Set include_package_data=True so wheels include vendor license files.

[jasongrout]

Vendor license info was included in #5213 (merge commit 7a3cbee), and is now available in the sdist package, but not in the wheel package. This commit makes the wheel packages include the vendor license files.

Generating the file list in the wheel before and after this change shows this change results in these additional files in the wheel:

pip/_vendor/README.rst
pip/_vendor/appdirs.LICENSE.txt
pip/_vendor/cachecontrol/LICENSE.txt
pip/_vendor/certifi/LICENSE
pip/_vendor/chardet/LICENSE
pip/_vendor/colorama/LICENSE.txt
pip/_vendor/distlib/LICENSE.txt
pip/_vendor/distro.LICENSE
pip/_vendor/html5lib/LICENSE
pip/_vendor/idna/LICENSE.rst
pip/_vendor/ipaddress.LICENSE
pip/_vendor/lockfile/LICENSE
pip/_vendor/msgpack/COPYING
pip/_vendor/packaging/LICENSE
pip/_vendor/packaging/LICENSE.APACHE
pip/_vendor/packaging/LICENSE.BSD
pip/_vendor/pep517/LICENSE
pip/_vendor/pkg_resources/LICENSE
pip/_vendor/progress/LICENSE
pip/_vendor/pyparsing.LICENSE
pip/_vendor/pytoml/LICENSE
pip/_vendor/requests/LICENSE
pip/_vendor/retrying.LICENSE
pip/_vendor/six.LICENSE
pip/_vendor/urllib3/LICENSE.txt
pip/_vendor/vendor.txt
pip/_vendor/webencodings/LICENSE

[jasongrout]

I'm not sure if this is the right way to fix this, but it works on the platform I'm developing on. If there is a better way to include the vendor license files in the wheel, please let me know.

[jasongrout]

The failing tests on windows indicate that this isn't enough of a fix to add license files to the wheel on all platforms. Any suggestions for what to do?

[chrahunt]

Closing and reopening since failing build logs were gone.

[pradyunsg]

Closing since this is out of date. Please feel free to submit an updated PR if this is still relevant! :)