message: fix: Update theme export in core package
  `@chakra-ui/theme` only has a default export, so if we want to export the theme from `@chakra-ui/core` like this line seems to be doing, it'll need to be updated to export the default export of `@chakra-ui/theme`.
diff: @@ -20,7 +20,7 @@ export * from "@chakra-ui/input"
  export * from "@chakra-ui/layout"
  export type { GridProps, ListProps } from "@chakra-ui/layout"
  export * from "@chakra-ui/media-query"
  -export * from "@chakra-ui/theme"
  +export {default as theme} from "@chakra-ui/theme"
  export * from "@chakra-ui/menu"
  export * from "@chakra-ui/modal"
  export * from "@chakra-ui/number-input"
  