0.8.1: dev dependency reference only by path (#375)

API Features

• Support is_in check in filter!/query! (#351)
• Allow any valid sqlite or pg connection string (#355)
• Add Many.set (#357)
• Allow Many.get after Many.delete (#356)
• Add support for dates (#348)
• impl PartialEq for AutoPk (#346)
• Create a ConnectionSpec from a database URI (#344)
• Add Backend.row_id_column (#329)

Library fixes & internal improvements

• Improve the comment on DataObjectOps::save (#350)
• Improve Many operation descriptions (#358)
• [butane_test_helper] Enhancements to improve API & testing (#363)
• Dependency updates
• Remove direct use of once_cell (#362)
• Use SQLite 3.35 DROP COLUMN (#340)
• Fix quoting of table names in queries (#338)
• [cli] return, not exit, from get_migrations (#335)