Update storybook monorepo to v6.4.21

Author: renovate[bot]

package.json

@@ -24,14 +24,14 @@
     "@babel/core": "7.17.2",
     "@babel/preset-react": "7.16.7",
     "@babel/runtime-corejs3": "7.17.2",
-    "@storybook/addon-actions": "6.4.19",
+    "@storybook/addon-actions": "6.4.21",
     "@storybook/addon-knobs": "6.4.0",
-    "@storybook/addon-links": "6.4.19",
-    "@storybook/addons": "6.4.19",
-    "@storybook/components": "6.4.19",
-    "@storybook/core-events": "6.4.19",
-    "@storybook/preact": "6.4.19",
-    "@storybook/theming": "6.4.19",
+    "@storybook/addon-links": "6.4.21",
+    "@storybook/addons": "6.4.21",
+    "@storybook/components": "6.4.21",
+    "@storybook/core-events": "6.4.21",
+    "@storybook/preact": "6.4.21",
+    "@storybook/theming": "6.4.21",
     "@types/react": "17.0.39",
     "@types/webpack-env": "1.16.3",
     "babel-loader": "8.2.3",
@@ -51,7 +51,7 @@
     "build-storybook": "build-storybook -s public -c test/.storybook"
   },
   "dependencies": {
-    "@storybook/client-api": "6.4.19",
+    "@storybook/client-api": "6.4.21",
     "preact": "10.6.5",
     "preact-render-to-string": "5.1.19",
     "react-dom": "17.0.2"