Bump smallvec from 0.6.8 to 0.6.9
Bump smallvec from 0.6.8 to 0.6.9

Bumps [smallvec](https://github.com/servo/rust-smallvec) from 0.6.8 to 0.6.9.
- [Release notes](https://github.com/servo/rust-smallvec/releases)
- [Commits](https://github.com/servo/rust-smallvec/compare/v0.6.8...v0.6.9)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
alex/otp-cop