feat: refactor to vanilla JS core

BREAKING CHANGES

- Adopts React 18's `useId`, making the library incompatible with React <18
- Switch to `tsup` from `microbundle` for bundling library. No longer exports a UMD version, just CJS and MJS

Features & Bug fixes

- Refactors core functionality to vanilla JS (with a React) adapter, which I think should fix #103 and fix #100
- Added `onExpandedChange` option
- Tries to detect if `getToggleProps` is used. If the toggle element ref can be accessed, the `aria-labelledby` attribute will be added to the collapse element
- Added `role="region"` to collapse
- Updated toggle props to pass the appropriate attributes to the element, whether it's a button or not