Bump sdd to 3.0.7 in Cargo.lock

`cargo deny` warns about `sdd` 3.0.4 being yanked. This upgrades it
to 3.0.7.

https://github.com/wvwwvwwv/scalable-delayed-dealloc/blob/main/CHANGELOG.md
describes 3.0.7 as "Fix a use-after-free issue when thread-local
storage is dropped." This seems worth bumping the version to in
Cargo.lock to be received in `--locked` builds.

Author: EliahKagan