update previous version

Author: svgeesus

worklets/Overview.bs

@@ -4,7 +4,7 @@ Status: ED
 Group: houdini
 ED: https://drafts.css-houdini.org/worklets/
 TR: http://www.w3.org/TR/worklets-1/
-Previous Version: http://www.w3.org/TR/2016/WD-worklets-1-20160607/
+Previous Version: https://www.w3.org/TR/2020/WD-worklets-1-20200908/
 Shortname: worklets
 Level: 1
 Abstract:  This specification defines an API for running scripts in stages of the rendering pipeline independent of the main javascript execution environment.