Bump pkg-config from 0.3.17 to 0.3.19 in /consensus/enclave/trusted

Bumps [pkg-config](https://github.com/rust-lang/pkg-config-rs) from 0.3.17 to 0.3.19.
- [Release notes](https://github.com/rust-lang/pkg-config-rs/releases)
- [Changelog](https://github.com/rust-lang/pkg-config-rs/blob/master/CHANGELOG.md)
- [Commits](rust-lang/pkg-config-rs@0.3.17...0.3.19)

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

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