build(deps): bump hmac from 0.8.0 to 0.8.1 (#454)

Bumps [hmac](https://github.com/RustCrypto/MACs) from 0.8.0 to 0.8.1.
- [Release notes](https://github.com/RustCrypto/MACs/releases)
- [Commits](RustCrypto/MACs@hmac-v0.8.0...hmac-v0.8.1)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Shella Stephens <shella@iqlusion.io>