refactor: add future annotations imports (#398)

##### SUMMARY

This adds future annotations imports to benefit from the modern python
typing system.

plugins/modules/firewall.py

@@ -4,6 +4,8 @@
 # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
 
 
+from __future__ import annotations
+
 DOCUMENTATION = """
 ---
 module: firewall
@@ -167,7 +169,6 @@ hcloud_firewall:
 """
 
 import time
-from typing import Optional
 
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.common.text.converters import to_native
@@ -180,7 +181,7 @@ from ..module_utils.vendor.hcloud.firewalls import BoundFirewall, FirewallRule
 class AnsibleHCloudFirewall(AnsibleHCloud):
     represent = "hcloud_firewall"
 
-    hcloud_firewall: Optional[BoundFirewall] = None
+    hcloud_firewall: BoundFirewall | None = None
 
     def _prepare_result(self):
         return {
@@ -324,7 +325,7 @@ class AnsibleHCloudFirewall(AnsibleHCloud):
                     "choices": ["absent", "present"],
                     "default": "present",
                 },
-                **super().base_module_arguments()
+                **super().base_module_arguments(),
             ),
             required_one_of=[["id", "name"]],
             required_if=[["state", "present", ["name"]]],