Update database_cleaner 1.2.0 -> 1.3.0

New Features/Changes

* Introduced `DatabaseCleaener::cleaninng` method that takes a block.
* Improved Sequel support and added more tests

Bug Fixes

* Fixed an issue with the `Transaction` strategy and Active Record where
  application-level transactions are not rolled back correctly.
* activerecord-oracle_enhanced-adapter now works again.