Make auto schedule loading compatible with Array format

[machisuke]

fixes #346

background

The auto-loading introduced in #337 supports Hash format schedule, but not Array format.

For example, with the bellow config/schedule.yml,

-
  name: 'my_first_job'
  class: 'MyFirstJob'
  cron: '1 * * * *'
  description: |
    my_first_job
-
  name: 'my_second_job'
  class: 'MySecondJob'
  cron: '2 * * * *'
  description: |
    my_second_job

the auto-loading causes the below error.

2022-07-11T08:58:27.831Z pid=22 tid=7ge WARN: NoMethodError: undefined method `[]=' for nil:NilClass
2022-07-11T08:58:27.831Z pid=22 tid=7ge WARN: /usr/local/bundle/gems/sidekiq-cron-1.6.0/lib/sidekiq/cron/job.rb:152:in `block in load_from_hash'
/usr/local/bundle/gems/sidekiq-cron-1.6.0/lib/sidekiq/cron/job.rb:151:in `each'
/usr/local/bundle/gems/sidekiq-cron-1.6.0/lib/sidekiq/cron/job.rb:151:in `inject'
/usr/local/bundle/gems/sidekiq-cron-1.6.0/lib/sidekiq/cron/job.rb:151:in `load_from_hash'
/usr/local/bundle/gems/sidekiq-cron-1.6.0/lib/sidekiq/cron/schedule_loader.rb:11:in `block (2 levels) in <main>'
/usr/local/bundle/gems/sidekiq-6.5.1/lib/sidekiq/component.rb:56:in `block in fire_event'
/usr/local/bundle/gems/sidekiq-6.5.1/lib/sidekiq/component.rb:55:in `each'
/usr/local/bundle/gems/sidekiq-6.5.1/lib/sidekiq/component.rb:55:in `fire_event'
/usr/local/bundle/gems/sidekiq-6.5.1/lib/sidekiq/cli.rb:105:in `run'
/usr/local/bundle/gems/sidekiq-6.5.1/bin/sidekiq:31:in `<top (required)>'
bin/sidekiq:29:in `load'
bin/sidekiq:29:in `<main>'

What

This PR solves the above problem so that both Hash- and Array-style definitions are auto-loaded without error.

[markets]

That makes sense to me! ✅

@sandip-mane @danilogco are you fine with that too?

[sandip-mane]

@markets the implementation looks good.

But I feel that instead of supporting the arrays through yml, we should raise an error for invalid hash format.

My opinion is we support only one format, either hash or arrays. Reason being: I don't like the idea of adding both these syntaxes to README it will create confusion.

What do you think?

[markets]

@sandip-mane thanks for your input! I get your point, but I think it feels even more natural to support both formats in the autoloader. Since we have 2 ways of loading jobs from the YAML, supporting both seems least surprising.

[sandip-mane]

Since we have 2 ways of loading jobs from the YAML, supporting both seems least surprising.

@markets sounds reasonable 👍