lint: Fixes from new ruff

The noqa comment was added manually to avoid
  A005 Module `json` shadows a Python standard-library module

Signed-off-by: Jussi Kukkonen <jkukkonen@google.com>

Author: jku

tuf/api/_payload.py

@@ -1222,7 +1222,7 @@ def __init__(
         self.number_of_bins = 2**bit_length
         # suffix_len is calculated based on "number_of_bins - 1" as the name
         # of the last bin contains the number "number_of_bins -1" as a suffix.
-        self.suffix_len = len(f"{self.number_of_bins-1:x}")
+        self.suffix_len = len(f"{self.number_of_bins - 1:x}")
 
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, SuccinctRoles):

tuf/api/serialization/json.py

@@ -8,6 +8,9 @@
 verification.
 """
 
+# We should not have shadowed stdlib json but that milk spilled already
+# ruff: noqa: A005
+
 import json
 from typing import Optional