Bump dependencies in composer.lock

Regenerate composer.lock to reflect dependency updates: guzzlehttp/guzzle 7.11.1 -> 7.12.3 (including guzzlehttp/psr7 requirement and polyfill bump), guzzlehttp/psr7 2.11.0 -> 2.12.3, guzzlehttp/test-server ^0.5 -> ^0.5.1, setasign/fpdi v2.6.7 -> v2.6.8 (and setasign/fpdf dev constraint ~1.8.6 -> ^1.9.0), smarty/smarty v5.8.0 -> v5.8.1. Timestamps and VCS references updated accordingly. This commit only updates the lockfile to pin newer upstream releases.

Author: mokesano