chore: 🤖 Pin storybook docs addon to a minor version (#1631)

The storybook docs addon is broken in 6.5.x currently. Pinning it to
6.3.x lets us to continue using storybook. See this github issue:
https://github.com/storybookjs/storybook/issues/17527

✅ Closes: ICU-7791

addons/rose/package.json

@@ -60,7 +60,7 @@
     "@storybook/addon-a11y": "^6.3.12",
     "@storybook/addon-actions": "^6.3.10",
     "@storybook/addon-controls": "^6.5.12",
-    "@storybook/addon-docs": "^6.3.8",
+    "@storybook/addon-docs": "~6.3.8",
     "@storybook/addons": "^6.3.9",
     "@storybook/api": "^6.3.12",
     "@storybook/cli": "^6.3.10",