Provide tarball containing submodules for releases
While packaging the latest 0.5.0~beta I was struggling a little bit, because the tarball (as can be downloaded from https://source.puri.sm/Librem5/chatty/-/tags) does not contain the sources of the submodules.
Here is a relevant gitlab issue https://gitlab.com/gitlab-org/gitlab/-/issues/300366
A suitable tarball can be generated with f.e. ninja -C _build dist
, which is also what GNOME expects to be uploaded to their ftp server (see https://wiki.gnome.org/MaintainersCorner/Releasing)