chore(deps): depend on serde_core instead of serde

[DaniPopes]

This crate does not make use of serde derive macros, thus it can depend on serde_core instead of serde to speed up users' compile times.

See the documentation of serde_core for more details.

[codspeed-hq]

CodSpeed Performance Report

Merging #527 will not alter performance

_{Comparing DaniPopes:serde_core (fe9e484) with main (401534e)¹}

Summary

✅ 351 untouched

Footnotes

1. No successful run was found on main (fe9e484) during the generation of this report, so 401534e was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩