Version 3.1.8

Additions:

• Laravel 5.8 support
• Allow passing of options to disk (#2060)
• Add remote temporary files for queued imports/exports
• Added config setting for default value binder
• Added config setting for database transaction handler
• Added Excel::raw()

Fixes

• Improve multiple rows from mapping handling + prevent errors on exporting json_array's
• Serialize eager load constraints
• Fixed callback validator and custom rule objects