Output instead of CombinedOutput when parsing helm version output

if there are warnings in the helm output (such as kubeconfig permissions too loose) it will cause the version to erroneously be detected as V2.

internal/helmutil/version.go

@@ -30,7 +30,7 @@ var helm3Detected func() bool
 
 func helmVersionCommand() bool {
 	cmd := exec.Command("helm", "version", "--short", "--client")
-	out, err := cmd.CombinedOutput()
+	out, err := cmd.Output()
 	if err != nil {
 		// Should not happen in normal cases (when helm is properly installed).
 		// Anyway, for now fallback to v2 for backward compatibility for helm-s3 users that are still on v2.