Hint: the '--setuptools' parameter in virtualenv changed.
15.1.0:
--setuptools DEPRECATED. Retained only for backward compatibility. This option has no effect.
20.0.5:
--setuptools version setuptools version to install, bundle for bundled (default: latest)
So removing '--setuptools' completely looks like a possible solution here.
Hint: the '--setuptools' parameter in virtualenv changed.
15.1.0:
--setuptools DEPRECATED. Retained only for backward compatibility.
This option has no effect.
20.0.5:
--setuptools version setuptools version to install, bundle for bundled (default: latest)
So removing '--setuptools' completely looks like a possible solution here.