avoid error when decrypting files with non-ascii character

src/documents/management/commands/change_storage_type.py

@@ -75,7 +75,7 @@ class Command(BaseCommand):
 
         for document in encrypted_files:
 
-            print(coloured("Decrypting {}".format(document), "green"))
+            print(coloured("Decrypting {}".format(document).encode('utf-8'), "green"))
 
             old_paths = [document.source_path, document.thumbnail_path]
             raw_document = GnuPG.decrypted(document.source_file, passphrase)