requirements.txt: bump Django and other dependency versions

Since Django 1.8 is now out of support, and we've cleaned up the issues,
bump the Django requirement to 1.11 and update other dependencies at the
same time.

Fixes [YOCTO #12696] (requires preceding commits)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>

README

@@ -12,8 +12,8 @@ Setup
 In order to make use of this application you will need:
 
 * Python 3.4+
-* Django 1.8.x - tested with 1.8.18; newer versions may work, but
-  the application has not been tested with 1.9 or newer.
+* Django 1.11.x - tested with 1.11.12; newer versions may work, but
+  the application has not been tested with 2.0 or newer.
 * RabbitMQ 3.6.x - tested with 3.6.10.
 * For production usage, a web server set up to host Django applications
   (not needed for local-only testing)

requirements.txt

@@ -3,25 +3,25 @@ anyjson==0.3.3
 billiard==3.5.0.3
 celery==4.1.0
 confusable-homoglyphs==2.0.2
-Django<1.9
+Django>1.11.0,<1.12
 django-cors-headers==1.1.0
 django-nvd3==0.9.7
 django-ranged-response==0.2.0
 django-registration==2.4.1
-django-reversion==1.9.3
-django-reversion-compare==0.5.6
+django-reversion==2.0.13
+django-reversion-compare==0.8.4
 django-simple-captcha==0.5.6
-djangorestframework==3.6.4
+djangorestframework==3.8.2
 gitdb==0.6.4
 GitPython==2.1.8
 Jinja2==2.10
 kombu==4.1.0
 MarkupSafe==1.0
 mysqlclient==1.3.12
-Pillow==5.0.0
-python-nvd3==0.14.2
-python-slugify==1.2.4
-pytz==2018.3
+Pillow==5.1.0
+python-nvd3==0.15.0
+python-slugify==1.2.5
+pytz==2018.4
 six==1.11.0
 smmap==0.9.0
 smmap2==2.0.3