Add changelog info

Author: akbansa

readme.txt

@@ -8,7 +8,7 @@ Author URI: https://www.gumlet.com
 Requires at least: 3.3
 Requires PHP: 5.6.3
 Tested up to: 6.3.1
-Stable tag: 1.3.11
+Stable tag: 1.3.12
 License: BSD-2
 License URI: http://opensource.org/licenses/BSD-2-Clause
 
@@ -141,6 +141,12 @@ If you need any help, you can reach out to us at support@gumlet.com.
 
 == Changelog ==
 
+= 1.3.12 =
+* Add Support for Gumlet video embeds.
+
+= 1.3.11 =
+* Update Pricing and free plan limits.
+
 = 1.3.10 =
 * Compatible with latest verson of WordPress.