net/py-zeroconf: update dependencies

• Starting with release 0.21.3, due to a bug, py-zeroconf has changed from using the netifaces module to using ifaddr, see https://github.com/jstasiak/python-zeroconf/commit/7c0500ee19869ce0e85e58a26b8fdb0868e0b142#diff-2eeaed663bd0d25b7e608891384b7298

Approved by: miwi (mentor)
Differential Revision: https://reviews.freebsd.org/D19014