Fix imports in pyproject.toml

[MaloChevillotte]

Fixes EXP-4274
Our new Python packaging that moved from setup.py to pyproject.toml was introduced with PR 26. We used the include-package-data which only imports non-.py file from the current directory. eppo_metric_schema.json is in the schema directory and was not imported when users ran pip install. That lead to Strava pinning to version 0.1.2 because our latest release throws back an error message. Potentially all customers using this package will be impacted when running pip install eppo_metrics_sync.

Current change should fix it as per Perplexity

Testing

• Verified package builds locally using python -m build, locally installed the package from eppo_metrics_sync-0.1.4.tar.gz and ran a sync to QA.