Added missing changelog entry.
Added missing changelog entry.

n054/php-markdown,queirozfcom/php-markdown-with-syntax-highlight,Kapeli/php-markdown,MWDelaney/bootstrap-3-shortcodes,filipstefansson/bootstrap-3-shortcodes,mariokonrad/php-markdown,filipstefansson/bootstrap-3-shortcodes,jockchou/php-markdown,robbieaverill/php-markdown,nazar-pc/php-markdown-next,MWDelaney/bootstrap-3-shortcodes,TypeFriendly/PHP-Markdown,drosenstark/php-markdown,itafroma/php-markdown,ashur/php-markdown,MWDelaney/bootstrap-3-shortcodes