feat(Checkbox): new component (#67)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

src/theme/index.ts

@@ -3,6 +3,7 @@ export { default as avatar } from './avatar'
 export { default as badge } from './badge'
 export { default as button } from './button'
 export { default as card } from './card'
+export { default as checkbox } from './checkbox'
 export { default as chip } from './chip'
 export { default as collapsible } from './collapsible'
 export { default as container } from './container'