fix: bump rustls-webpki to 0.103.13 to fix RUSTSEC-2026-0104 (#1209)

## Summary

- Bumps `rustls-webpki` from `0.103.12` to `0.103.13` in `Cargo.lock`
- Fixes RUSTSEC-2026-0104: reachable panic in certificate revocation
list parsing
- Advisory published 2026-04-22; the previous cargo audit fix PR (#1190)
predated it

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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: lym953