Package: elan Version: 3.0.0-2 I hope to update the rust-toml package to version 0.8 soon. I have tested that elan builds with the dependency bumped.
However, given https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1061550 I think it probably makes more sense for your package to switch back to using toml 0.5, as your upstream expects. toml 0.5 is maintained in a seperate source package and is unlikely to be going away any time soon. The debdiff for doing so is posted over in the other bug.