Upgrade django-picklefield

Remove anyjson and pyparsing

Remove explicit kombu since it is celery dependency

requirements.txt

 Django==1.11.28
-anyjson==0.3.3
 celery==4.2.1
-django-picklefield==0.3.0
-kombu==4.2.0
+django-picklefield==1.1.0
 html5lib==0.999
 psycopg2==2.8.3
-pyparsing==2.0.0
 python-dateutil>=1.5
 python3-openid==3.0.10
 gunicorn==19.9