Bump react from 16.12.0 to 17.0.2 in /example

Bumps [react](https://github.com/facebook/react/tree/HEAD/packages/react) from 16.12.0 to 17.0.2.
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/v17.0.2/packages/react)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

example/package.json

@@ -7,7 +7,7 @@
     "broadcast-channel": "^2.1.8",
     "history": "^4.7.2",
     "prop-types": "^15.6.2",
-    "react": "^16.4.1",
+    "react": "^16.14.0",
     "react-cross-client-router": "link:..",
     "react-dom": "^16.4.1",
     "react-router-dom": "^5.2.0",

example/yarn.lock

@@ -6500,10 +6500,10 @@ react-scripts@^1.1.4:
   optionalDependencies:
     fsevents "^1.1.3"
 
-react@^16.4.1:
-  version "16.12.0"
-  resolved "https://registry.yarnpkg.com/react/-/react-16.12.0.tgz#0c0a9c6a142429e3614834d5a778e18aa78a0b83"
-  integrity sha512-fglqy3k5E+81pA8s+7K0/T3DBCF0ZDOher1elBFzF7O6arXJgzyu/FW+COxFvAWXJoJN9KIZbT2LXlukwphYTA==
+react@^16.14.0:
+  version "16.14.0"
+  resolved "https://registry.yarnpkg.com/react/-/react-16.14.0.tgz#94d776ddd0aaa37da3eda8fc5b6b18a4c9a3114d"
+  integrity sha512-0X2CImDkJGApiAlcf0ODKIneSwBPhqJawOa5wCtKbu7ZECrmS26NvtSILynQ66cgkT/RJ4LidJOc3bUESwmU8g==
   dependencies:
     loose-envify "^1.1.0"
     object-assign "^4.1.1"