feat: ✨ introduces early access headers in stack config

Author: nadeem-cs

index.d.ts

@@ -55,6 +55,7 @@ export interface Config {
     live_preview?: LivePreview;
     plugins?: ContentstackPlugin[];
     fetchOptions?: FetchOptions;
+    ea_headers?: string[]
 }
 // Stack Config
 export interface StackConfig {

src/core/stack.js

@@ -101,6 +101,9 @@ export default class Stack {
                     if (typeof stack_arguments[0].branch === "string" && stack_arguments[0].branch !== undefined) {
                         this.headers.branch = stack_arguments[0].branch
                     }
+                    if (typeof stack_arguments[0].ea_headers == "object" && Array.isArray(stack_arguments[0].ea_headers) && stack_arguments[0].ea_headers.length > 0) {
+                        this.headers['x-header-ea'] = stack_arguments[0].ea_headers.join(',')
+                    }
                     this.environment = stack_arguments[0].environment;
                     return this;
                 } else {