In https://github.com/ostreedev/ostree/pull/2633 I realized
that our CI only builds git of libostree or git of rust-bindings,
not git of both. And we definitely want to test the latter too,
so e.g. the Rust tests *also* become tests for changes to the C code.
There were some changes to the sys API for introspection fixes.
And add a feature for the current release, which is something
I'll add to the checklist for releases.