message: Add note about migrating the package.
diff: @@ -21,11 +21,13 @@ You can use this package normally, which means installing it and adding a script
  But alternatively (and this is useful for testing) you can use npx:
  **Use a git branch**:
  +
  ```sh
  npx -p chromaui/chromatic-cli#master chromatic --dev
  ```
  **Use a debug version on npm**:
  +
  ```sh
  npx -p chromatic#next chromatic
  ```
  @@ -50,6 +52,8 @@ Do not run this based on a github pull_request event. If you do, the commit and
  You can also use the environment variable: `CHROMATIC_PROJECT_TOKEN`
  +> Note: this option was previously known as "--app-code". If you encounter an error referring to this, you should upgrade to the latest version of the Chromatic CLI. See [Migrating to the new CLI package](#migrating-to-the-new-cli-package).
  +
  ### Storybook options
  ```
  @@ -58,6 +62,7 @@ You can also use the environment variable: `CHROMATIC_PROJECT_TOKEN`
  ```
  Deprecated options (for tunneled builds):
  +
  ```
  --script-name [name], -s The npm script that starts your Storybook [storybook]
  --exec <command>, -e Alternatively, a full command to run to start your storybook
  @@ -139,3 +144,21 @@ To facilitate upgrading in the future, removing and adding features, this is the
  - Any new features will have to be on Chromatic production before they could be used in this package
  - We can add feature flags to be able to test new functionality
  - Chromatic production can not remove any features this package depends on until after the usage has been removed from this package in addition to a grace period to allow users to upgrade
  +
  +### Migrating to the new CLI package
  +
  +This package was previously named `storybook-chromatic`. If you still have `storybook-chromatic` installed, you should remove it and install `chromatic` instead:
  +
  +**With npm:**
  +
  +```
  +npm uninstall --dev storybook-chromatic
  +npm install --dev chromatic
  +```
  +
  +**With yarn:**
  +
  +```
  +yarn remove --dev storybook-chromatic
  +yarn add --dev chromatic
  +```
  