Update CHANGELOG.md

Author: daattali

CHANGELOG.md

@@ -4,6 +4,7 @@
 - Fixed bug where navbar secondary level dropdown items didn't inherit te same colour as the primary navbar links
 - Fixed bug where the navbar "burger" collapsed button didn't always revert back to a light colour
 - Fixed bug where using an image as a navbar title did not render in GitHub Project pages that did not have a custom domain
+- Fixed issue where image thumbnails on the feed page were always forced into a square rather than maintaining a proper image aspect ratio
 
 ## v5.0.0 (2020-09-15)