Changed whitelist to allowlist in tox
Changed whitelist to allowlist in tox

Replace tox's whitelist_externals by allowlist_externals option:
https://github.com/tox-dev/tox/blob/master/docs/changelog.rst#v3180-2020-07-23

Change-Id: I4e85c700278fbd68ea38b0c5b036db2c2a72ef76

openstack/cinder,openstack/cinder,mahak/cinder,mahak/cinder