fix:[#384] disallow updating built-in stacks

- throw error if stack is built-in
- add english translation for update built-in stack error

cmd/stacks.go

@@ -407,6 +407,11 @@ func updateStack(cmd *cobra.Command, args []string) error {
 		return error
 	}
 
+	if stack.BuiltIn {
+		cmdr.Error.Println(apx.Trans("stacks.update.error.builtIn"))
+		os.Exit(126)
+	}
+
 	if base == "" {
 		if !assumeYes {
 			cmdr.Info.Printfln(apx.Trans("stacks.update.info.askBase"), stack.Base)

locales/en.yml

@@ -268,6 +268,7 @@ stacks:
       noPkgManager: "No package manager specified."
       pkgManagerDoesNotExist: "The specified package manager does not exist. Create
         it with 'apx pkgmanagers new' or contact the system administrator."
+      builtIn: "Built-in stacks cannot be modified."
     info:
       askBase: "Type a new base or confirm the current one (%s):"
       askPkgManager: "Choose a new package manager or confirm the current one (%s):"