Log Message:
databases/ruby-sequel: update to 5.30.0

Update ruby-sequel to 5.30.0.

=== 5.30.0 (2020-03-01)

* Remove specs and old release notes from the gem to reduce gem size by over 40% \ 
(jeremyevans)

* When using Database#transaction :retry_on, call :before_retry option if \ 
retrying even if :num_retries is nil (jcmfernandes) (#1678)

* Support generated columns on SQLite 3.31+ using :generated_always_as and \ 
:generated_type options (jeremyevans)