Update pytz from 2017.3 to 2018.3

pyup-bot · renzon · commit 2eb82dfb7a20 · 2018-03-01T09:35:11.000-03:00
diff --git a/requirements.txt b/requirements.txt
@@ -1,6 +1,6 @@
 Django==2.0.2
 dj_database_url==0.4.2
-pytz==2017.3
+pytz==2018.3
 python_box==3.1.1
 six==1.11.0
 gunicorn==19.7.1
