Bump zerovec from 0.10.2 to 0.10.4

Bumps [zerovec](https://github.com/unicode-org/icu4x) from 0.10.2 to 0.10.4.
- [Release notes](https://github.com/unicode-org/icu4x/releases)
- [Changelog](https://github.com/unicode-org/icu4x/blob/main/CHANGELOG.md)
- [Commits](https://github.com/unicode-org/icu4x/commits/ind/[email protected])

---
updated-dependencies:
- dependency-name: zerovec
  dependency-type: indirect
...

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