fix: pin composer lock to php 8.2 compatible symfony clock

[cat-ph]

Summary

Fix CI after composer.lock was checked into master with symfony/clock v8.0.0, which requires PHP 8.4 and breaks composer install on the 8.2/8.3 jobs.

This keeps composer.json unchanged, so downstream consumers on PHP 8.4+ can still resolve Clock 8 if they want to. Only the checked-in lockfile changes for this repo.

Changes

• downgrade locked symfony/clock from v8.0.0 to v7.4.8
• add symfony/polyfill-php83 as required by that resolution
• leave composer.json constraints alone

Verification

• composer install --prefer-dist --no-progress

[cat-ph]

I think unit tests didn't run in #114 - 8.2 and 8.3 are broken when using clock v8 (noticed it on my branch in #109)

[marandaneto]

ups sorry