Describe the bug

As of version 0.8.1, POT installs its benchmarks outside of the OT namespace when using setup.py. For example, running

/usr/bin/python3.10 setup.py install --root /foo/pot

will result in the following actions

copying /blabla/.pybuild/cpython3_3.10_pot/build/benchmarks/__init__.py -> /foo/pot/usr/lib/python3.10/dist-packages/benchmarks
copying /blabla/.pybuild/cpython3_3.10_pot/build/benchmarks/benchmark.py ->/foo/pot/usr/lib/python3.10/dist-packages/benchmarks
copying /blabla/.pybuild/cpython3_3.10_pot/build/benchmarks/emd.py ->/foo/pot/usr/lib/python3.10/dist-packages/benchmarks
copying /blabla/.pybuild/cpython3_3.10_pot/build/benchmarks/sinkhorn_knopp.py -> /foo/pot/usr/lib/python3.10/dist-packages/benchmarks

(along with the expected files from the ot subdirectory, of course). Since the benchmark directory ends up outside of the ot subdirectory, it easily clashes with other packages.

This did not happen with version 0.8.0 or earlier.

To Reproduce

Steps to reproduce the behavior:

1. /usr/bin/python3.10 setup.py install --root /foo/pot.
2. Observe files installed in /foo/pot/usr/lib/python3.10/dist-packages/benchmarks (i.e. outside of the /foo/pot/usr/lib/python3.10/dist-packages/ot tree).

Expected behavior

POT should not claim the global "benchmarks" namespace.

Environment (please complete the following information):

• OS (e.g. MacOS, Windows, Linux): Linux
• Python version: 3.10
• How was POT installed (source, pip, conda): source
• Build command you used (if compiling from source): See above