v3.21.0

Enhancements

• Added a subtitle and thumbnail prop to Page (#1880)

Bug fixes

• Fixed accessibility issue with ChoiceList errors not being correctly connected to the inputs (#1824)
• Fixed Tab aria-controls pointing to a non-existent Panel id (#1869)
• Fixed Toast accessibility issue by moving aria-live prop to ToastManager (#1873)

Code quality

• Use @shopify/typescript-configs as the base of tsconfig.json for the project (#1829)