[css-animations-1] Add link to latest published WD

Author: birtles

css-animations-1/Overview.bs

@@ -20,6 +20,7 @@ Level: 1
 Group: csswg
 TR: https://www.w3.org/TR/css-animations-1/
 ED: https://drafts.csswg.org/css-animations/
+Previous Version: https://www.w3.org/TR/2018/WD-css-animations-1-20181011/
 Previous Version: https://www.w3.org/TR/2017/WD-css-animations-1-20171130/
 Previous Version: https://www.w3.org/TR/2013/WD-css3-animations-20130219/
 Previous Version: https://www.w3.org/TR/2012/WD-css3-animations-20120403/