Add support for Publisher Common ID Module in Sharethrough bid adapte…

…r documentation (#2432)

- Related feature PR [here](placeholder)

Story: [#175125639](https://www.pivotaltracker.com/story/show/175125639)

dev-docs/bidders/sharethrough.md

@@ -8,7 +8,7 @@ media_types     : native
 schain_supported: true
 tcf2_supported  : true
 title           : Sharethrough
-userIds         : unifiedId
+userIds         : pubCommonId, unifiedId
 usp_supported   : true
 pbjs            : true
 pbs             : true