chore: updated changelog to note premium update

Author: bfintal

readme.txt

@@ -239,9 +239,9 @@ Nope. Stackable only works with Gutenberg, the new WordPress editor.
 == Changelog ==
 
 = 3.1.1 =
-* New: Added back ability to change the column order when columns collapse in mobile
-* New: Added Post Taxonomies in dynamic content
 * New: Added link option to the Image Block
+* New: Added back ability to change the column order when columns collapse in mobile (premium)
+* New: Added Post Taxonomies in dynamic content (premium)
 * Fixed: Trigger when all display conditions are met is not triggering properly
 * Fixed: Entrance animation speeds and delay do not take effect correctly
 * Fixed: Column gap and fit columns options now work in Feature Grid block