Update hmac requirement from 0.8 to 0.9
Update hmac requirement from 0.8 to 0.9

Updates the requirements on [hmac](https://github.com/RustCrypto/MACs) to permit the latest version.
- [Release notes](https://github.com/RustCrypto/MACs/releases)
- [Commits](https://github.com/RustCrypto/MACs/compare/hmac-v0.8.0...hmac-v0.9.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
sfackler/rust-postgres,sfackler/rust-postgres