Fix zeroconf github URL in requirements.txt
Fix zeroconf github URL in requirements.txt

mrpau/kolibri,indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri,mrpau/kolibri,learningequality/kolibri,indirectlylit/kolibri,learningequality/kolibri,learningequality/kolibri,mrpau/kolibri,learningequality/kolibri,indirectlylit/kolibri