fix(flags): Replace slices.Contains with sliceContains custom func

cmd/kubens/flags.go

@@ -18,7 +18,6 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"slices"
 	"strings"
 
 	"github.com/ahmetb/kubectx/internal/cmdutil"
@@ -58,10 +57,10 @@ func parseArgs(argv []string) Op {
 	} else if n == 2 {
 		// {namespace} -f|--force
 		name := argv[0]
-		force := slices.Contains([]string{"-f", "--force"}, argv[1])
+		force := sliceContains([]string{"-f", "--force"}, argv[1])
 
 		if !force {
-			if !slices.Contains([]string{"-f", "--force"}, argv[0]) {
+			if !sliceContains([]string{"-f", "--force"}, argv[0]) {
 				return UnsupportedOp{Err: fmt.Errorf("unsupported arguments %q", argv)}
 			}
 
@@ -82,3 +81,14 @@ func getSwitchOp(v string, force bool) Op {
 	}
 	return SwitchOp{Target: v, Force: force}
 }
+
+// sliceContains returns true if slice contains item.
+// todo replace with slices.Contains after upgrading to go 1.21
+func sliceContains(slice []string, item string) bool {
+	for _, v := range slice {
+		if v == item {
+			return true
+		}
+	}
+	return false
+}