Properly cast input in `update_all`

The documentation claims that given values go through "normal AR type
casting and serialization", which to me implies
`serialize(cast(value))`, not just serialization. The docs were changed
to use this wording in #22492. The tests I cited in that PR (which is
the same test modified in this commit), is worded in a way that implies
it should be using `cast` as well.

It's possible that I originally meant "normal type casting" to imply
just the call to `serialize`, but given that `update_all(archived:
params['archived'])` seems to be pretty common, I'm inclined to make
this change as long as no tests are broken from it.

activerecord/CHANGELOG.md

@@ -1,3 +1,9 @@
*   `update_all` will now pass its values to `Type#cast` before passing them to
    `Type#serialize`. This means that `update_all(foo: 'true')` will properly
    persist a boolean.

    *Sean Griffin*

*   Add new error class `StatementTimeout` which will be raised
    when statement timeout exceeded.

activerecord/lib/active_record/sanitization.rb

@@ -110,7 +110,8 @@ def expand_hash_conditions_for_aggregates(attrs) # :doc:
        def sanitize_sql_hash_for_assignment(attrs, table) # :doc:
          c = connection
          attrs.map do |attr, value|
            value = type_for_attribute(attr.to_s).serialize(value)
            type = type_for_attribute(attr.to_s)
            value = type.serialize(type.cast(value))
            "#{c.quote_table_name_for_assignment(table, attr)} = #{c.quote(value)}"
          end.join(", ")
        end

activerecord/test/cases/relation_test.rb

@@ -288,13 +288,18 @@ def type
        :string
      end

      def cast(value)
        raise value unless value == "value from user"
        "cast value"
      end

      def deserialize(value)
        raise value unless value == "type cast for database"
        "type cast from database"
      end

      def serialize(value)
        raise value unless value == "value from user"
        raise value unless value == "cast value"
        "type cast for database"
      end
    end