Bump react-dom from 16.12.0 to 17.0.2 in /example

Bumps [react-dom](https://github.com/facebook/react/tree/HEAD/packages/react-dom) 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-dom)

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

Author: dependabot[bot]

example/package.json

@@ -9,7 +9,7 @@
     "prop-types": "^15.6.2",
     "react": "^16.4.1",
     "react-cross-client-router": "link:..",
-    "react-dom": "^16.4.1",
+    "react-dom": "^16.13.0",
     "react-router-dom": "^5.2.0",
     "react-scripts": "^1.1.4"
   },

example/yarn.lock

@@ -6407,15 +6407,15 @@ react-dev-utils@^5.0.2:
     strip-ansi "3.0.1"
     text-table "0.2.0"
 
-react-dom@^16.4.1:
-  version "16.12.0"
-  resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-16.12.0.tgz#0da4b714b8d13c2038c9396b54a92baea633fe11"
-  integrity sha512-LMxFfAGrcS3kETtQaCkTKjMiifahaMySFDn71fZUNpPHZQEzmk/GiAeIT8JSOrHB23fnuCOMruL2a8NYlw+8Gw==
+react-dom@^16.13.0:
+  version "16.13.0"
+  resolved "https://registry.yarnpkg.com/react-dom/-/react-dom-16.13.0.tgz#cdde54b48eb9e8a0ca1b3dc9943d9bb409b81866"
+  integrity sha512-y09d2c4cG220DzdlFkPTnVvGTszVvNpC73v+AaLGLHbkpy3SSgvYq8x0rNwPJ/Rk/CicTNgk0hbHNw1gMEZAXg==
   dependencies:
     loose-envify "^1.1.0"
     object-assign "^4.1.1"
     prop-types "^15.6.2"
-    scheduler "^0.18.0"
+    scheduler "^0.19.0"
 
 react-error-overlay@^4.0.1:
   version "4.0.1"
@@ -6944,10 +6944,10 @@ sax@^1.2.1, sax@^1.2.4, sax@~1.2.1:
   resolved "https://registry.yarnpkg.com/sax/-/sax-1.2.4.tgz?dl=https://registry.yarnpkg.com/sax/-/sax-1.2.4.tgz#2816234e2378bddc4e5354fab5caa895df7100d9"
   integrity sha1-KBYjTiN4vdxOU1T6tcqold9xANk=
 
-scheduler@^0.18.0:
-  version "0.18.0"
-  resolved "https://registry.yarnpkg.com/scheduler/-/scheduler-0.18.0.tgz#5901ad6659bc1d8f3fdaf36eb7a67b0d6746b1c4"
-  integrity sha512-agTSHR1Nbfi6ulI0kYNK0203joW2Y5W4po4l+v03tOoiJKpTBbxpNhWDvqc/4IcOw+KLmSiQLTasZ4cab2/UWQ==
+scheduler@^0.19.0:
+  version "0.19.1"
+  resolved "https://registry.yarnpkg.com/scheduler/-/scheduler-0.19.1.tgz#4f3e2ed2c1a7d65681f4c854fa8c5a1ccb40f196"
+  integrity sha512-n/zwRWRYSUj0/3g/otKDRPMh6qv2SYMWNq85IEa8iZyAv8od9zDYpGSnpBEjNgcMNq6Scbu5KfIPxNF72R/2EA==
   dependencies:
     loose-envify "^1.1.0"
     object-assign "^4.1.1"