Upgrade storybook to v6.5

Ran `npx sb upgrade` to upgrade storybook from v5.3 to v6.5.
Answer `Yes` to use webpack5 manager.

Author: rohit-nair

app/.storybook/main.js

@@ -15,4 +15,7 @@ module.exports = {
       },
     },
   ],
+  core: {
+    builder: 'webpack5'
+  }
 };

app/package.json

@@ -51,12 +51,14 @@
     "styled-components": "5.1.1"
   },
   "devDependencies": {
-    "@storybook/addon-actions": "5.3.19",
-    "@storybook/addon-docs": "5.3.19",
-    "@storybook/addon-links": "5.3.19",
-    "@storybook/addons": "5.3.19",
-    "@storybook/preset-create-react-app": "3.1.2",
-    "@storybook/react": "5.3.19",
+    "@storybook/addon-actions": "6.5.5",
+    "@storybook/addon-docs": "6.5.5",
+    "@storybook/addon-links": "6.5.5",
+    "@storybook/addons": "6.5.5",
+    "@storybook/builder-webpack5": "6.5.5",
+    "@storybook/manager-webpack5": "6.5.5",
+    "@storybook/preset-create-react-app": "4.1.1",
+    "@storybook/react": "6.5.5",
     "@testing-library/jest-dom": "5.11.5",
     "@testing-library/react": "11.1.1",
     "@testing-library/user-event": "12.2.0",
@@ -87,7 +89,8 @@
     "prettier": "2.1.2",
     "sass": "1.43.4",
     "ts-protoc-gen": "0.12.0",
-    "typescript": "4.1.6"
+    "typescript": "4.1.6",
+    "webpack": "5"
   },
   "eslintConfig": {
     "extends": "react-app",