new release: bunch of fixes/changes

What's Changed

• error for when changing server_default to non-null and nullable to false by @lolopinto in #1616
• Missing custom sql in generated schema.sql by @lolopinto in #1618
• ability to indicate which custom_sql revisions are added to schema.sql by @lolopinto in #1619
• fix include_rev by @lolopinto in #1620
• [auto_schema] squash all by @lolopinto in #1621
• fix file name by @lolopinto in #1622
• fix test by @lolopinto in #1624
• integrate squash all into CLI by @lolopinto in #1623
• pass database to squash by @lolopinto in #1625
• misc auto_schema changes by @lolopinto in #1627

Full Changelog: v0.1.5...v0.1.6