Modernize some Python constructs (#876)

* Update __future__ import, remove __metaclass__ assignment.

* Removing obsolete encoding comment.

* Remove unneccessary object inheritance.

plugins/modules/certificate_complete_chain.py

@@ -1,14 +1,9 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
-#
 # Copyright (c) 2018, Felix Fontein <felix@fontein.de>
 # GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-from __future__ import absolute_import, division, print_function
-
-
-__metaclass__ = type
+from __future__ import annotations
 
 
 DOCUMENTATION = r"""
@@ -164,7 +159,7 @@ except ImportError:
     HAS_CRYPTOGRAPHY = False
 
 
-class Certificate(object):
+class Certificate:
     """
     Stores PEM with parsed certificate.
     """
@@ -275,7 +270,7 @@ def load_PEM_list(module, path, fail_on_error=True):
             return []
 
 
-class CertificateSet(object):
+class CertificateSet:
     """
     Stores a set of certificates. Allows to search for parent (issuer of a certificate).
     """