Drift 2.23.0

This drift release contains smaller fixes and new features:

Core query builder:

• Allow building compound select statements in Dart.
• Support NULLS FIRST and NULLS LAST in manager API.

Generator and command line tools:

• Fix custom companion names on @DataClassName not being recognized.
• Improve schema exports to resolve default values instead of embedding their source.
• Update dependencies to support latest dart_style version.
• Fix generating dialect-specific code when only a single dialect (that isn't sqlite3) is enabled.