Runs pyupgrade to Python 3.8+ and adds a hook for it

src/documents/management/commands/decrypt_documents.py

@@ -55,7 +55,7 @@ class Command(BaseCommand):
 
         for document in encrypted_files:
 
-            print("Decrypting {}".format(document).encode("utf-8"))
+            print(f"Decrypting {document}".encode())
 
             old_paths = [document.source_path, document.thumbnail_path]
 

src/documents/management/commands/loaddata_stdin.py

@@ -17,4 +17,4 @@ class Command(LoadDataCommand):
     def find_fixtures(self, fixture_label):
         if fixture_label == "-":
             return [("-", None, "-")]
-        return super(Command, self).find_fixtures(fixture_label)
+        return super().find_fixtures(fixture_label)