BREAKING - the kiba CLI is deprecated

The kiba CLI is deprecated in favor of the more modern Kiba.parse programmatic API [#74, #81].

The programmatic API allows everything the "command" mode supported, plus much more, and actually encourage better coding practices. For instance:

• API mode allows to pass live variables (rather than just ENV configuration from command line or JSON configs from files)
• Doing so permits to wrap resources open/close around running a job
• API mode makes it easier to run testing on an ETL process (via minitest/rspec) directly in-process (which allows stubbing/webmock etc), rather than via a command call
• API mode enforces use of clean modules with explicit loading, rather than polluting the top-level namespace with global methods
• API mode allows to run jobs from Sidekiq or background job systems, from an HTTP call (if the job is fast), without necessarily waiting for a command line binary to run - this supports more dynamic interactions (e.g. a job is created in reaction to an external event received via HTTP or a websocket)

A temporary kiba-legacy-cli gem is available (https://github.com/thbar/kiba-legacy-cli) to ease migration, but the recommendation is really to migrate over and use Kiba.parse directly, as described in the current documentation.

Kiba now defaults to StreamingRunner

Introduced in v2.0.0 [#44] to ensure a transform could yield N rows for 1 input row, and improved in v2.5.0 [#57] to help implement "buffering transforms", the StreamingRunner is now made the default to process the jobs [#83].

This change is expected to be backward compatible and will help with reusability & features of ETL components.

Ruby compatibility notice

• Kiba now officially supports MRI Ruby 2.4+ (although 2.3 will still work for now), JRuby 9.2+ or TruffleRuby.
• You may get warnings with Ruby 2.7 and errors with Ruby 2.8+. See [#85] for status on Ruby 3 keyword arguments support.