user.is_authenticated is no longer a method

Apparently this is now a property, so we don't need to call it. We can
just use it.

contest/views.py

@@ -17,7 +17,7 @@ from .forms import UpdateRefForm, QSOForm, QSOFormWithTime, CustomUserCreationFo
 
 
 def index(request):
-    if request.user.is_authenticated():
+    if request.user.is_authenticated:
         return HttpResponseRedirect(reverse("contest:index"))
 
     return render(request, "index.html", {"loginForm": AuthenticationForm()})