Upgrade underlying ransack gem from 2.6.0 to 3.x

[steveyken]

In order to run ransack_ui on Rails 7.1+ we need to update ransack gem to at least.

There are two major updates to address

• Remove deprecated #search method

Further reading

• https://github.com/activerecord-hackery/ransack/blob/main/CHANGELOG.md
• https://github.com/activerecord-hackery/ransack/issues/1403

After this update, ransack_ui will no longer be compatible with Rails 6.0

[steveyken]

Merged PR #24 increased version from 2.x to 3.x