Update chrono to pass audit

[balroggg]

Update chrono dependency and reduce its features to pass audit.

cargo audit
    Fetching advisory database from `https://github.com/RustSec/advisory-db.git`
      Loaded 433 security advisories (from /home/balrog/.cargo/advisory-db)
    Updating crates.io index
    Scanning Cargo.lock for vulnerabilities (55 crate dependencies)

[balroggg]

Fix #108