0.6.0: pep517 based build fails

[kloczek]

By defailt build is doing build in isolation and looks like in venv is needed six (which would be good to get rid off sooner or later).

+ /usr/bin/python3 -sBm build -w
* Creating venv isolated environment...
* Installing packages in isolated environment... (setuptools >= 40.8.0, wheel)
* Getting dependencies for wheel...
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/pep517/in_process/_in_process.py", line 363, in <module>
    main()
  File "/usr/lib/python3.8/site-packages/pep517/in_process/_in_process.py", line 345, in main
    json_out['return_val'] = hook(**hook_input['kwargs'])
  File "/usr/lib/python3.8/site-packages/pep517/in_process/_in_process.py", line 130, in get_requires_for_build_wheel
    return hook(config_settings)
  File "/tmp/build-env-w14v7u79/lib64/python3.8/site-packages/setuptools/build_meta.py", line 162, in get_requires_for_build_wheel
    return self._get_build_requires(
  File "/tmp/build-env-w14v7u79/lib64/python3.8/site-packages/setuptools/build_meta.py", line 143, in _get_build_requires
    self.run_setup()
  File "/tmp/build-env-w14v7u79/lib64/python3.8/site-packages/setuptools/build_meta.py", line 267, in run_setup
    super(_BuildMetaLegacyBackend,
  File "/tmp/build-env-w14v7u79/lib64/python3.8/site-packages/setuptools/build_meta.py", line 158, in run_setup
    exec(compile(code, __file__, 'exec'), locals())
  File "setup.py", line 5, in <module>
    import multipledispatch
  File "/home/tkloczko/rpmbuild/BUILD/multipledispatch-0.6.0/multipledispatch/__init__.py", line 1, in <module>
    from .core import dispatch
  File "/home/tkloczko/rpmbuild/BUILD/multipledispatch-0.6.0/multipledispatch/core.py", line 3, in <module>
    from .dispatcher import Dispatcher, MethodDispatcher, ambiguity_warn
  File "/home/tkloczko/rpmbuild/BUILD/multipledispatch-0.6.0/multipledispatch/dispatcher.py", line 3, in <module>
    from .conflict import ordering, ambiguities, super_signature, AmbiguityWarning
  File "/home/tkloczko/rpmbuild/BUILD/multipledispatch-0.6.0/multipledispatch/conflict.py", line 2, in <module>
    from .variadic import isvariadic
  File "/home/tkloczko/rpmbuild/BUILD/multipledispatch-0.6.0/multipledispatch/variadic.py", line 1, in <module>
    import six
ModuleNotFoundError: No module named 'six'

As quick workaround can be applied build execution with --no-isolation

+ /usr/bin/python3 -sBm build -w --no-isolation
* Getting dependencies for wheel...
running egg_info
creating multipledispatch.egg-info
writing manifest file 'multipledispatch.egg-info/SOURCES.txt'
writing manifest file 'multipledispatch.egg-info/SOURCES.txt'
* Building wheel...
running bdist_wheel
running build
running build_py
creating build
creating build/lib
creating build/lib/multipledispatch
copying multipledispatch/__init__.py -> build/lib/multipledispatch
copying multipledispatch/conflict.py -> build/lib/multipledispatch
copying multipledispatch/core.py -> build/lib/multipledispatch
copying multipledispatch/dispatcher.py -> build/lib/multipledispatch
copying multipledispatch/utils.py -> build/lib/multipledispatch
copying multipledispatch/variadic.py -> build/lib/multipledispatch
running install
running install_lib
creating build/bdist.linux-x86_64
creating build/bdist.linux-x86_64/wheel
creating build/bdist.linux-x86_64/wheel/multipledispatch
running install_egg_info
running egg_info
writing manifest file 'multipledispatch.egg-info/SOURCES.txt'
Copying multipledispatch.egg-info to build/bdist.linux-x86_64/wheel/multipledispatch-0.6.0-py3.8.egg-info
running install_scripts
Successfully built multipledispatch-0.6.0-py3-none-any.whl