fix(cmd): errorlint linter

#### Description

errorlint linter in cmd/helm

Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>

cmd/helm/helm.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main // import "helm.sh/helm/v4/cmd/helm"
 
 import (
+	"errors"
 	"log/slog"
 	"os"
 
@@ -41,7 +42,8 @@ func main() {
 	}
 
 	if err := cmd.Execute(); err != nil {
-		if cerr, ok := err.(helmcmd.CommandError); ok {
+		var cerr helmcmd.CommandError
+		if errors.As(err, &cerr) {
 			os.Exit(cerr.ExitCode)
 		}
 		os.Exit(1)

cmd/helm/helm_test.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	"bytes"
+	"errors"
 	"os"
 	"os/exec"
 	"runtime"
@@ -60,7 +61,8 @@ func TestCliPluginExitCode(t *testing.T) {
 		cmd.Stderr = stderr
 		err := cmd.Run()
 
-		exiterr, ok := err.(*exec.ExitError)
+		exiterr := &exec.ExitError{}
+		ok := errors.As(err, &exiterr)
 		if !ok {
 			t.Fatalf("Unexpected error type returned by os.Exit: %T", err)
 		}