Add Bangla WordPress Plugin Development Tutorial Playlist (#10013)

* Add Bangla WordPress Plugin Development Tutorial Playlist

* Fix title

courses/free-courses-bn.md

@@ -307,4 +307,5 @@ Shikkhangon BD
 * [WordPress Customization Bangla Tutorial](https://www.youtube.com/playlist?list=PLbC4KRSNcMno7NzhTgGhoZtRjLiHUo8m4) - Learn Hunter
 * [Wordpress Bangla Tutorial Course for beginner to advanced level](https://www.youtube.com/playlist?list=PLeCz-UdZ0uzQVPdQN-mWnz8896BdYMqAf) - Freelancer Mannan
 * [WordPress Theme Development Tutorial Bangla ](https://www.youtube.com/playlist?list=PLSNRR4BKcowD6A-U_ll9ayJWqOEz3XD8l) - Procoder BD
+* [WordPress Plugin Development](https://www.youtube.com/playlist?list=PLSNRR4BKcowCkeAxfdtTsLqwR0LJYwDaz) - Procoder BD