createMigration method
Produce a migration from the difference between existing migrations and the latest schema
Implementation
String? createMigration(LibraryReader library, List<SqliteFields> fieldses, {int? version}) {
final newSchema = _createNewSchema(library, fieldses, version: version);
return migrationGenerator.generate(
library,
null,
newSchema: newSchema,
version: version,
);
}