In case anyone still wants to force the upgrade before they produce an update with a fix you can get the Growl Detective here: http://bit.ly/yhYnku
14-03-2012 22:14 - edited 14-03-2012 22:15
asaivorymeeks' solution works fine for me on Lion 10.7.3, Skype 22.214.171.1245 and Growl 1.3.1. Downloaded the Growl 1.3.1. SDK and replaced the Growl.framework folder in the Skype application. Thanks!
Get the SDK file here: http://growl.info/downloads