Use AR Arel table to type cast booleans in order to avoid deprecation warning

[thom-oman]

DEPRECATION WARNING: Passing a column to `quote` has been deprecated. It is only used for type casting, which should be handled elsewhere. See https://github.com/rails/arel/commit/6160bfbda1d1781c3b08a33ec4955f170e95be11 for more information. (called from update_most_recents at /Users/eproulx/code/statesman/lib/statesman/adapters/active_record.rb:144)
Arel performing automatic type casting is deprecated, and will be removed in Arel 8.0. If you are seeing this, it is because you are manually passing a value to an Arel predicate, and the `Arel::Table` object was constructed manually. The easiest way to remove this warning is to use an `Arel::Table` object returned from calling `arel_table` on an ActiveRecord::Base subclass.

If you're certain the value is already of the right type, change `attribute.eq(value)` to `attribute.eq(Arel::Nodes::Quoted.new(value))` (you will be able to remove that in Arel 8.0, it is only required to silence this deprecation warning).

You can also silence this warning globally by setting `$arel_silence_type_casting_deprecation` to `true`. (Do NOT do this if you are a library author)

If you are passing user input to a predicate, you must either give an appropriate type caster object to the `Arel::Table`, or manually cast the value before passing it to Arel.

also

DEPRECATION WARNING: Passing a column to `quote` has been deprecated. It
is only used for type casting, which should be handled elsewhere.

#403

[danwakefield]

No idea if this messes up anyone using string instead of bool as a column type.
Major bump to avoid the version breaking them?