Failed to download the package from https://github.com/fsitok/gds3xtrude.git/tags/v0.0.8.
There needs to be a file called 'grain.xml' below this URL. It needs to have the XML format of a KLayout package definition file.
If you are addressing a GIT repository, please check whether you are using the SVN style access URLs: use '.../repo.git/trunk' for the master and '../repo.git/branches/x' for branch 'x'.