add create-react-app --help info for local file path --scripts-version support (#4015)

* add `create-react-app --help` info for local file path --scripts-version

* make example path `../my-react-scripts` for local file path --help info

packages/create-react-app/createReactApp.js

@@ -89,6 +89,11 @@ const program = new commander.Command(packageJson.name)
         'my-react-scripts'
       )}`
     );
+    console.log(
+      `      - a local path relative to the current working directory: ${chalk.green(
+        'file:../my-react-scripts'
+      )}`
+    );
     console.log(
       `      - a .tgz archive: ${chalk.green(
         'https://mysite.com/my-react-scripts-0.8.2.tgz'