Update artifact ID (again) to "koji".
Update artifact ID (again) to "koji".

This lets the majority of users who have "koji" installed, rather than the
"koji-plugin" version, see that there have been updates to the plugin.

Also, this new release will add a wiki URL, so the plugin will remain visible in
the update centre.

Finally, I got approval from the the maintainer to make these changes & release.

jenkinsci/koji-plugin,jenkinsci/koji-plugin