requiremests: Update to newest versions

Updates:
  * Django 1.11.8 to 1.11.9
  * Django Rest Framework 3.7.3 to 3.7.7
  * certifi 2017.11.5 to 2018.1.18
  * owslib 0.15.0 to 0.16.0
  * raven 6.3.0 to 6.5.0

requirements.txt

@@ -2,21 +2,21 @@
 #
 #   prequ update
 #
-certifi==2017.11.5        # via requests
+certifi==2018.1.18        # via requests
 chardet==3.0.4            # via requests
-django==1.11.8
+django==1.11.9
 django-environ==0.4.4
 django-filter==1.1.0
-djangorestframework==3.7.3
+djangorestframework==3.7.7
 djangorestframework-gis==0.12
 idna==2.6                 # via requests
 lxml==4.1.1
-owslib==0.15.0
+owslib==0.16.0
 psycopg2==2.7.3.2
 pyproj==1.9.5.1           # via owslib
 python-dateutil==2.6.1    # via owslib
 pytz==2017.3
-raven==6.3.0
+raven==6.5.0
 requests==2.18.4          # via owslib
 six==1.11.0               # via django-environ, djangorestframework-gis, python-dateutil
 urllib3==1.22             # via requests