Release 0.81.4

See https://docs.lamin.ai/changelog

What's Changed

• ✨ Allow to synchronize via st_size if st_mtime is not present in UPath.stat() by @Koncopd in #913
• 🐛 Prepare for deletion of the storage_id column from the instance table by @Koncopd in #915

Full Changelog: 0.81.3...0.81.4