Pylint: abide by useless-object-inheritance warnings

Inheriting from object is a remainder of Python 2 habits and is just
clutter in Python 3.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

scripts/abi_check.py

@@ -29,7 +29,7 @@ from types import SimpleNamespace
 import xml.etree.ElementTree as ET
 
 
-class AbiChecker(object):
+class AbiChecker:
     """API and ABI checker."""
 
     def __init__(self, old_version, new_version, configuration):

tests/scripts/check-files.py

@@ -17,7 +17,7 @@ import codecs
 import sys
 
 
-class FileIssueTracker(object):
+class FileIssueTracker:
     """Base class for file-wide issue tracking.
 
     To implement a checker that processes a file as a whole, inherit from
@@ -188,7 +188,7 @@ class MergeArtifactIssueTracker(LineIssueTracker):
         return False
 
 
-class IntegrityChecker(object):
+class IntegrityChecker:
     """Sanity-check files under the current directory."""
 
     def __init__(self, log_file):