Fix warning issued by AS log subscriber 7.1 and make bold again

[Hampei]

Fixed for 7.2 in https://github.com/rom-rb/rom-sql/commit/62867221448f657519cd4526a725d81e9dfed697

But the warning is already present from rails 7.1.2 (7.2 is even an error, not a warning).

The previous fix turned the positional boolean into {color: true}, but the only keys that do anything are bold/italic/underline, and the old true stood for bold, see: https://github.com/rails/rails/blob/v7.1.5.2/activesupport/lib/active_support/log_subscriber.rb#L190 and https://github.com/rails/rails/blob/v7.1.5.2/activesupport/lib/active_support/log_subscriber.rb#L70

Arguments remain the same for for 7.2 https://github.com/rails/rails/blob/v7.2.2.2/activesupport/lib/active_support/log_subscriber.rb#L170 and 8.0 https://github.com/rails/rails/blob/v7.2.2.2/activesupport/lib/active_support/log_subscriber.rb#L170

No spec changes, since there is no appraisals, nor any existing specs around this.