Dependency hardening: pin minimum safe dependency versions

Hi, thanks for ChatDev. Low-priority dependency-hardening note, not an active vulnerability report - a default install resolves to safe versions today.

These declarations also permit older versions with known CVEs; pinning a minimum prevents an accidental downgrade (please test compatibility):

• requests: pin >= 2.32.4 (e.g. CVE-2024-35195 and 1 more)

(Low-priority dependency-hygiene note - feel free to close if not useful, happy to send a PR.)