feat: added support for branches

[robertolosanno-e2x]

Fixes #

NEW FEATURES | UPGRADE NOTES | ENHANCEMENTS | BUG FIXES | EXPERIMENTS

[robertolosanno-e2x]

Hi @demeyerthom,
I tested the change with the following code, just need to update the variable branch := "main" with a different branch

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	"github.com/labd/contentstack-go-sdk/management"
)

func main() {
	apiKey := os.Getenv("CONTENTSTACK_API_KEY")
	if apiKey == "" {
		log.Fatal("CONTENTSTACK_API_KEY environment variable is required")
	}

	managementToken := os.Getenv("CONTENTSTACK_MANAGEMENT_TOKEN")
	if managementToken == "" {
		log.Fatal("CONTENTSTACK_MANAGEMENT_TOKEN environment variable is required")
	}

	cfg := management.ClientConfig{
		BaseURL: "https://api.contentstack.io", // or your region specific URL
	}

	client, err := management.NewClient(cfg)
	if err != nil {
		log.Fatalf("Error creating client: %v", err)
	}

	branch := "main"
	stackAuth := management.StackAuth{
		ApiKey:          apiKey,
		ManagementToken: managementToken,
		Branch:          branch, // specify your branch here
	}

	instance, err := client.Stack(&stackAuth)
	if err != nil {
		log.Fatalf("Error creating stack instance: %v", err)
	}

	contentTypes, err := instance.ContentTypeFetchAll(context.Background())
	if err != nil {
		log.Fatalf("Error fetching content types: %v", err)
	}

	fmt.Printf("Found %d content types in branch '%s':\n", len(contentTypes), branch)
	for _, ct := range contentTypes {
		fmt.Printf("- %s (UID: %s)\n", ct.Title, ct.UID)
	}
}