Fix changelog index

Author: jim-parry

user_guide_src/source/changelogs/index.rst

@@ -20,7 +20,7 @@ Release Date: April 04, 2019
 **Next release of CodeIgniter4**
 
 
-:doc:`See all the changes. </changelogs/next>`
+:doc:`See all the changes. </changelogs/v4.0.0-beta.2>`
 
 Version 4.0.0-beta.1
 ====================================================