4.0.2: Fix parsing durations from string with UTF8 micro character

What's Changed

• Update pyo3 requirement from 0.22.0 to 0.23.3 by @dependabot in #348
• Fix parsing of microseconds with UTF8 symbol and parsing negative durations by @ChristopherRabotin in #350

Full Changelog: 4.0.1...4.0.2