Drop support for python 3.4 and 3.5, since they're now unsupported too anyway

.travis.yml

@@ -3,8 +3,6 @@ dist: bionic # use LTS 18.04
 
 python:
     - "2.7"
-    - "3.4"
-    - "3.5"
     - "3.6"
     - "3.7"
 

README.rst

@@ -7,7 +7,7 @@ django-helpdesk - A Django powered ticket tracker for small businesses.
 .. image:: https://codecov.io/gh/django-helpdesk/django-helpdesk/branch/master/graph/badge.svg
   :target: https://codecov.io/gh/django-helpdesk/django-helpdesk
 
-Copyright 2009-2018 Ross Poulton and django-helpdesk contributors. All Rights Reserved.
+Copyright 2009-2019 Ross Poulton and django-helpdesk contributors. All Rights Reserved.
 See LICENSE for details.
 
 django-helpdesk was formerly known as Jutda Helpdesk, named after the
@@ -63,10 +63,10 @@ Installation
 `django-helpdesk` requires:
 
 * Django 1.11.x
-* either Python 2.7 or 3.4+
+* either Python 2.7 or 3.6+ (likely 3.4+ still works though, but unsupported)
 
 **NOTE REGARDING PYTHON VERSION:**
-The recommended combination is Python 3.4+ with Django 1.11.
+The recommended combination is Python 3.6+ with Django 1.11.
 Support for Python 2 will end in the next versions of both `django-helpdesk`
 and Django itself (Django 2.0), so users and developers are encouraged to begin
 transitioning to Python 3 if have not already. New projects should definitely
@@ -74,7 +74,7 @@ use Python 3!
 
 **NOTE REGARDING DJANGO VERSION:**
 The recommended release is Django 1.11. However, there initial support of
-Django 2.0 as of version 0.2.7 if you'd like to try it out.
+Django 2.x as of version 0.2.7 if you'd like to try it out.
 Please report any bugs you find!
 
 You can quickly install the latest stable version of `django-helpdesk`