-r requirements.txt
django==2.1.2
bumpversion==0.5.3
wheel==0.32.2
django-environ==0.4.5
radon==2.4.0
pytz==2018.5

-r requirements.txt
django==2.1.2
bumpversion==0.5.3
wheel==0.32.2
django-environ==0.4.5
radon==2.4.0
pytz==2018.6

Update pytz from 2018.5 to 2018.6
Update pytz from 2018.5 to 2018.6