feat: Added zone GCP fact

* Added fact about zone, where the instance is located
* Extended unit test covering this new fact
* Note: GCP does not provide any information about instance type

src/rhsmlib/facts/cloud_facts.py

@@ -181,6 +181,11 @@ def get_gcp_facts(self) -> Dict[str, str]:
                         facts["gcp_project_number"] = values["google"]["compute_engine"]["project_number"]
                     else:
                         log.debug("GCP project_number not found in JWT token")
+                    # zone where the machine is located
+                    if "zone" in values["google"]["compute_engine"]:
+                        facts["gcp_zone"] = values["google"]["compute_engine"]["zone"]
+                    else:
+                        log.debug("GCP zone not found in JWT token")
                 else:
                     log.debug("GCP google.compute_engine on found in JWT token")
         return facts

test/rhsmlib/facts/test_cloud_facts.py

@@ -349,6 +349,8 @@ def test_get_gcp_facts(self, mock_get_metadata_from_cache, mock_write_token_to_c
         self.assertEqual(facts["gcp_project_id"], "fair-kingdom-308514")
         self.assertIn("gcp_project_number", facts)
         self.assertEqual(facts["gcp_project_number"], 161958465613)
+        self.assertIn("gcp_zone", facts)
+        self.assertEqual(facts["gcp_zone"], "us-east1-b")
 
     @patch("cloud_what.providers.aws.requests.Session", name="mock_session_class")
     def test_get_not_aws_instance(self, mock_session_class):