Bump mimalloc from 0.1.29 to 0.1.39 in /rust/sbp2json

Bumps [mimalloc](https://github.com/purpleprotocol/mimalloc_rust) from 0.1.29 to 0.1.39.
- [Release notes](https://github.com/purpleprotocol/mimalloc_rust/releases)
- [Commits](purpleprotocol/mimalloc_rust@v0.1.29...v0.1.39)

---
updated-dependencies:
- dependency-name: mimalloc
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>