fix: fixed readme script format

Author: MaitriGurey1

README.md

@@ -6,11 +6,13 @@ The Contentstack App SDK allows you to customize your applications. This documen
 
 Include the compiled version of the extension client library by adding the following line to your application.
 
+```html
 <script
     src="https://unpkg.com/@contentstack/[email protected]/dist/index.js"
     integrity="sha512-wlEBUkZA+vdcHXRTK69fZvK44c5Y8KeU/kw9OOShWNDjddtrIB8a1lfbLjH5nKWQqkWZ2L9VYEqr96P7qx3ZZg=="
     crossorigin="anonymous"
 ></script>
+```
 
 To include the App SDK in your project, you need to run the following command: