Test under gnome-shell 3.36 needed

Originally posted by @mwilck in https://github.com/projecthamster/hamster-shell-extension/issues/319#issuecomment-593486468

3.36: Ubuntu 20.04 LTS

Do we have any information whether our 3.34 code works with 3.36?

Please feel free to add any (positive or negative) feedback here.