message: docs: fix package name in the migration guide
diff: @@ -51,9 +51,9 @@ code, you can safely remove them and update Chakra UI to v1.
  ```diff
  "dependencies": {
  "@chakra-ui/core": "next",
  +- "@emotion/core": "10.x",
  - "@emotion/styled": "10.X",
  -- "@emotion/theming": "10.x",
  -- "@emotion/core": "10.x"
  +- "emotion-theming": "10.x"
  }
  ```
  