Adding docs plugin to existing package

[avinashresearch1]

I have already published a Julia package using PkgTemplates but at the time I did not include the plugin for docs. I was wondering if there is any procedure to update the package to include docs?

[nickrobinson251]

updating existing packages is a long requested feature but unfortunately not one we've added yet (#16)

I would like to add this feature one day. I did start working on it a long time ago, and that branch of code is still around (#288) - i'm not sure if it works but you could give it a try.