always use datetime.date.isoformat to generate filename

fixes #267

Signed-off-by: Oliver Lippert <info@trusty.codes>

src/documents/models.py

@@ -11,7 +11,6 @@ from django.conf import settings
 from django.contrib.auth.models import User
 from django.db import models
 from django.utils import timezone
-from django.utils.timezone import is_aware
 from django.utils.translation import gettext_lazy as _
 from documents.parsers import get_default_file_extension
 
@@ -210,10 +209,8 @@ class Document(models.Model):
         verbose_name_plural = _("documents")
 
     def __str__(self):
-        if is_aware(self.created):
-            created = timezone.localdate(self.created).isoformat()
-        else:
-            created = datetime.date.isoformat(self.created)
+        created = datetime.date.isoformat(self.created)
+
         if self.correspondent and self.title:
             return f"{created} {self.correspondent} {self.title}"
         else: