tag of v0.2.1

v0.2.0 — uutils adoption

v0.1.0 — First release

Memory-safe Rust reimplementation of all 14 Linux shadow-utils tools.
Drop-in replacement for GNU shadow-utils.

Highlights:
- All 14 tools: passwd, useradd, userdel, usermod, groupadd, groupdel,
  groupmod, pwck, grpck, chage, chpasswd, chfn, chsh, newgrp
- Single multicall binary (894 KB stripped)
- 562 tests (unit, integration, property-based, fuzz)
- unsafe_code = deny (only PAM/crypt FFI exempted)
- Atomic file writes, password zeroing, audit logging
- Debian + RPM packaging
- Docker test matrix: Debian, Alpine (musl), Fedora (SELinux)
- MIT license, GPL clean-room development