Lock web-console to 2.0.0.beta1 for the first 4.2 beta

The console on exception code isn't available on the stable releases
yet. Lock it for now, so the beta users get a sneak peak of the console
features.
[ActiveJob] Fix test syntax
[ActionMailer] Rename ActionMailer::DelayedDeliveryJob to ActionMailer::DeliveryJob
[ActiveJob] require files in logging.rb
[ActiveJob] Convert ActiveJob::Arguments into module
[ActiveJob] remove ruby warnings
[ActiveJob] make the resque-scheduler optional
[ActiveJob] Use globalid gem
[ActiveJob] Fix tests for sucker_punch
[ActiveJob] Add deserialize_arguments method to job
[ActiveJob] raise DeserializationError when got an error deserializing
Merge pull request #16532 from gsamokovarov/lock-web-console-for-4.2.0.beta1

Lock web-console to 2.0.0.beta1 for the first 4.2 beta
[ActiveJob] require global_id/railtie
Dont encourage people to run without autoflush in production
Merge pull request #16485 from seuros/activejob

Integrate ActiveJob / DeliverLater / GlobalID with Rails
Merge branch 'master' of github.com:rails/rails
Add CHANGELOG entry for #deliver_later
Merge pull request #16525 from kaspth/partial-release-prep

Prepare for partial release.
Merge pull request #16294 from bf4/code_tools

Update, unify, encapsulate, and fix various code tools in Rails
Merge pull request #16481 from sgrif/sg-change-default-timestamps

Change the default `null` value for timestamps