databases/py-schemachange: Update to 4.3.3

Switch the build backend from setuptools to hatchling, matching
upstream's move to pyproject.toml with the hatchling build system.

Changelog: https://github.com/Snowflake-Labs/schemachange/blob/v4.3.3/CHANGELOG.md

Approved by: dch (mentor)
Closes: https://github.com/freebsd/freebsd-ports/pull/563