Bump smallvec from 1.8.0 to 1.8.1 (#1409)

Bumps [smallvec](https://github.com/servo/rust-smallvec) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/servo/rust-smallvec/releases)
- [Commits](https://github.com/servo/rust-smallvec/compare/v1.8.0...v1.8.1)

---
updated-dependencies:
- dependency-name: smallvec
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>