Use lowercase formatting

Author: albanbochsler

tests/test_admin.py

@@ -1947,7 +1947,7 @@ def test_sidebar_image_ratio_format(self):
         context = {}
         height, width, context = get_aspect_ratio_and_download_url(context=context, detail=True, file=image, height=40, width=40)
         self.assertIsInstance(context['sidebar_image_ratio'], str)
-        expected_ratio = '%.6F' % (image.width / 210)
+        expected_ratio = '%.6f' % (image.width / 210)
         self.assertEqual(context['sidebar_image_ratio'], expected_ratio)
         self.assertEqual(context['sidebar_image_ratio'], '0.476190')