Update to django-cas-server 1.1 w Django 2.1 support

requirements/base.in

@@ -1,12 +1,13 @@
 boto
 boto3
 django
-django-autocomplete-light
-django-appconf
 django-anymail
+django-appconf
+django-autocomplete-light
 django-avatar
 django-bootstrap3
 django-braces
+django-cas-server
 django-compressor
 django-countries
 django-crispy-forms
@@ -17,12 +18,12 @@ django-leaflet
 django-multipleselectfield
 django-multiupload
 django-phonenumber-field
-django-storages
 django-registration-redux
+django-storages
 djangorestframework
 djangorestframework-gis
-gunicorn
 gevent
+gunicorn
 pip-tools
 psycopg2-binary
 python-memcached

requirements/base.txt

@@ -17,6 +17,7 @@ django-autocomplete-light==3.3.2
 django-avatar==4.1.0
 django-bootstrap3==11.0.0
 django-braces==1.13.0
+django-cas-server==1.1.0
 django-compressor==2.2
 django-countries==5.3.2
 django-crispy-forms==1.7.2
@@ -38,6 +39,7 @@ greenlet==0.4.15          # via gevent
 gunicorn==19.9.0
 idna==2.7                 # via requests
 jmespath==0.9.3           # via boto3, botocore
+lxml==4.3.3               # via django-cas-server
 phonenumbers==8.9.14      # via django-phonenumber-field
 pillow==5.2.0             # via django-avatar
 pip-tools==3.1.0
@@ -47,9 +49,10 @@ python-memcached==1.59
 pytz==2018.5              # via babel, django
 raven==6.9.0
 rcssmin==1.0.6
-requests==2.19.1          # via django-anymail
+requests-futures==0.9.9   # via django-cas-server
+requests==2.19.1          # via django-anymail, django-cas-server, requests-futures
 rjsmin==1.0.12
 s3transfer==0.1.13        # via boto3
-six==1.11.0               # via django-anymail, django-extensions, django-geojson, djangorestframework-gis, pip-tools, python-dateutil, python-memcached
+six==1.11.0               # via django-anymail, django-cas-server, django-extensions, django-geojson, djangorestframework-gis, pip-tools, python-dateutil, python-memcached
 urllib3==1.23             # via botocore, requests
 whitenoise==4.1