Update storybook monorepo to v5.3.21

Author: renovate-bot

package.json

@@ -38,10 +38,10 @@
   "devDependencies": {
     "@babel/core": "7.9.0",
     "@hot-loader/react-dom": "16.13.0",
-    "@storybook/addon-actions": "5.3.18",
-    "@storybook/addon-links": "5.3.18",
-    "@storybook/addons": "5.3.18",
-    "@storybook/react": "5.3.18",
+    "@storybook/addon-actions": "5.3.21",
+    "@storybook/addon-links": "5.3.21",
+    "@storybook/addons": "5.3.21",
+    "@storybook/react": "5.3.21",
     "@types/react": "16.9.31",
     "@welldone-software/why-did-you-render": "4.0.6",
     "babel-eslint": "10.1.0",