Remove encoding header

Fixes #2996

InvenTree/order/test_views.py

@@ -1,8 +1,5 @@
 """ Unit tests for Order views (see views.py) """
 
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
 from django.test import TestCase
 from django.urls import reverse
 from django.contrib.auth import get_user_model