Limit compatibility to Helm =>v3.0.0,<4.0.0 (#1039) (#1071)

This is a backport of PR #1039 as merged into main (13791ec).
SUMMARY
Helm v4 is a major version with backward-incompatible changes, including to the flags and output of the Helm CLI and to the SDK. This version is currently not supported in the kubernetes.core. This PR is related to #1038 and is a short-term solution to mark compatibility explicitly
ISSUE TYPE

Bugfix Pull Request
Docs Pull Request

COMPONENT NAME

helm
helm_template
helm_info
helm_repository
helm_pull
helm_registry_auth
helm_plugin
helm_plugin_info

ADDITIONAL INFORMATION
Added `validate_helm_version()`` method to AnsibleHelmModule that enforces version constraint >=3.0.0,<4.0.0.
Fails fast with clear error message: "Helm version must be >=3.0.0,<4.0.0, current version is {version}"
Some modules (i.e. helm_registry_auth) technically is compatible with Helm v4, but validation was added to all helm modules.
Partially coauthored by GitHub Copilot with Claude Sonnet 4 model.
Addresses issue #1038

Reviewed-by: Bianca Henderson <beeankha@gmail.com>
Reviewed-by: Mike Graves <mgraves@redhat.com>

plugins/module_utils/helm.py

@@ -202,6 +202,24 @@ class AnsibleHelmModule(object):
             return m.group(1)
         return None
 
+    def validate_helm_version(self):
+        """
+        Validate that Helm version is >=3.0.0 and <4.0.0.
+        Helm 4 is not yet supported.
+        """
+        helm_version = self.get_helm_version()
+        if helm_version is None:
+            self.fail_json(msg="Unable to determine Helm version")
+
+        if (LooseVersion(helm_version) < LooseVersion("3.0.0")) or (
+            LooseVersion(helm_version) >= LooseVersion("4.0.0")
+        ):
+            self.fail_json(
+                msg="Helm version must be >=3.0.0,<4.0.0, current version is {0}".format(
+                    helm_version
+                )
+            )
+
     def get_values(self, release_name, get_all=False):
         """
         Get Values from deployed release