fix(canendar): subtitle supports reactive

[cc-hearts]

fix: subTitle supports responsive switching when international language changes

close #12423

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files	Coverage Δ
packages/vant/src/calendar/Calendar.tsx	89.81% <100.00%> (+0.14%)	⬆️

... and 2 files with indirect coverage changes

📢 Thoughts on this report? Let us know!.

[chenjiahan]

Is this a breaking change? The title param of month-show event is changed.

The previous type was string, but now the type is Ref<string>

[cc-hearts]

this is a breaking change. the title should change responsively with locale changes.

The title type didn't change, that was my mistake.

[cc-hearts]

🤯 I did a lot of breaking change.

For subTitle assignments, use shallowReactive instead of ref. This way subTitle.text can be declared using ref.

[chenjiahan]

We can not introduce any breaking changes in a minor or patch release, so we can only make forward-compatible changes.

[cc-hearts]

Thanks to your suggestion, I removed breaking change.

[chenjiahan]

Thanks!