sqlite-utils 4.0rc1 adds migrations and nested transactions

sqlite-utils 4.0rc1 introduces two significant features: support for database migrations and nested transactions. The migration functionality, derived from the sqlite-migrate package, allows users to define and execute schema changes programmatically using a Python API, enhancing the library's capabilities for managing SQLite databases. This release is crucial for practitioners as it simplifies database schema evolution and improves transaction handling, which are essential for building robust applications.