[chore] Restrict Storybook version for Renovate (#171453)

Renovate bot keeps updating Storybook in #169655 to 7.x which has
[significant breaking
changes](https://github.com/storybookjs/storybook/blob/next/MIGRATION.md#from-version-65x-to-700),
CI failures, and requires Webpack 5. This upgrade will require a human
due to how our SB is setup.

[Renovate
Docs](https://docs.renovatebot.com/configuration-options/#allowedversions)

renovate.json

@@ -462,7 +462,8 @@
         "Team:Operations",
         "release_note:skip"
       ],
-      "enabled": true
+      "enabled": true,
+      "allowedVersions": "<7.0"
     },
     {
       "groupName": "react-query",
@@ -647,4 +648,4 @@
       "enabled": true
     }
   ]
-}
+}