Community plug-ins are handled quite a bit differently since they aren't created by our internal development team.
"Community plug-ins are open source projects that are developed and supported by the IBM UrbanCode development community."
https://github.com/UrbanCode/Venafi-UCD - This is the location of the plugin source code. For this particular plugin, there isn't a "released" version of the plugin available so you would have to create it yourself using the source code.
The source code on the github page along with our documentation on creating plugins should help you put the actual plugin .zip file together. Keep in mind, community plugins are not supported by the UrbanCode Deploy support team because they aren't created by IBM.