chore: upgrade storybook version used in rose

addons/rose/package.json

@@ -35,10 +35,10 @@
     "@glimmer/component": "^1.0.0",
     "@glimmer/tracking": "^1.0.0",
     "@hashicorp/structure-icons": "^1.8.1",
-    "@storybook/addon-actions": "^5.3.18",
-    "@storybook/addon-docs": "^5.3.18",
-    "@storybook/addon-knobs": "^5.3.18",
-    "@storybook/ember": "^5.3.18",
+    "@storybook/addon-actions": "^6.0.21",
+    "@storybook/addon-docs": "^6.0.21",
+    "@storybook/addon-knobs": "^6.0.21",
+    "@storybook/ember": "^6.0.21",
     "@storybook/ember-cli-storybook": "^0.2.1",
     "babel-eslint": "^10.0.3",
     "broccoli-asset-rev": "^3.0.0",