dogpile.cache: dogpile.cache 0.9.1 introduced pep517 regression

dogpile.cache 0.9.1 introduced pep517 regression which prevented its installation on some setups:

Collecting dogpile.cache>=0.6.5
  Downloading http://mirror.gra1.ovh.openstack.org/pypifiles/packages/e6/65/fa4a947926034cb4af5f469c376a21728b7fd8de4668fed757c3586f0eef/dogpile.cache-0.9.1.tar.gz (329 kB)
  Installing build dependencies: started
  Installing build dependencies: finished with status 'done'
  Getting requirements to build wheel: started
  Getting requirements to build wheel: finished with status 'error'

:stderr:   ERROR: Command errored out with exit status 1:
   command: /home/zuul/test-python/bin/python /home/zuul/test-python/lib/python3.6/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpx9zntfdw
       cwd: /tmp/pip-install-9ep3va87/dogpile.cache
  Complete output (10 lines):
  Traceback (most recent call last):
    File "/home/zuul/test-python/lib/python3.6/site-packages/pip/_vendor/pep517/_in_process.py", line 257, in <module>
      main()
    File "/home/zuul/test-python/lib/python3.6/site-packages/pip/_vendor/pep517/_in_process.py", line 240, in main
      json_out['return_val'] = hook(**hook_input['kwargs'])
    File "/home/zuul/test-python/lib/python3.6/site-packages/pip/_vendor/pep517/_in_process.py", line 85, in get_requires_for_build_wheel
      backend = _build_backend()
    File "/home/zuul/test-python/lib/python3.6/site-packages/pip/_vendor/pep517/_in_process.py", line 76, in _build_backend
      obj = getattr(obj, path_part)
  AttributeError: module 'setuptools.build_meta' has no attribute '__legacy__'
  ----------------------------------------
ERROR: Command errored out with exit status 1: /home/zuul/test-python/bin/python /home/zuul/test-python/lib/python3.6/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /tmp/tmpx9zntfdw Check the logs for full command output.
WARNING: You are using pip version 20.0.2; however, version 20.1 is available.

Full report at https://zuul.opendev.org/t/openstack/build/0a2a5ca6414f4e56b9508322cf01c9f4