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/modules/helm_registry_auth.py

@@ -20,7 +20,7 @@ author:
   - Yuriy Novostavskiy (@yurnov)
 
 requirements:
-  - "helm (https://github.com/helm/helm/releases) => 3.8.0"
+  - "helm (https://github.com/helm/helm/releases) >= 3.8.0, <4.0.0"
 
 description:
   -  Helm registry authentication module allows you to login C(helm registry login) and logout C(helm registry logout) from a Helm registry.
@@ -194,6 +194,9 @@ def main():
         supports_check_mode=True,
     )
 
+    # Validate Helm version >=3.0.0,<4.0.0
+    module.validate_helm_version()
+
     changed = False
 
     host = module.params.get("host")