build(deps): bump @types/react-dom from 16.9.2 to 16.9.4

Bumps [@types/react-dom](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react-dom) from 16.9.2 to 16.9.4.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/react-dom)

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

Author: dependabot-preview[bot]

package.json

@@ -15,7 +15,7 @@
     "@types/node": "12.11.5",
     "@types/ramda": "^0.26.33",
     "@types/react": "^16.9.9",
-    "@types/react-dom": "16.9.2",
+    "@types/react-dom": "16.9.4",
     "apollo-client": "2.6.3",
     "aws-amplify": "^1.2.2",
     "aws-appsync": "^2.0.1",

yarn.lock

@@ -2301,20 +2301,13 @@
   dependencies:
     ts-toolbelt "^4.12.0"
 
-"@types/react-dom@*":
+"@types/react-dom@*", "@types/react-dom@16.9.4":
   version "16.9.4"
   resolved "https://registry.yarnpkg.com/@types/react-dom/-/react-dom-16.9.4.tgz#0b58df09a60961dcb77f62d4f1832427513420df"
   integrity sha512-fya9xteU/n90tda0s+FtN5Ym4tbgxpq/hb/Af24dvs6uYnYn+fspaxw5USlw0R8apDNwxsqumdRoCoKitckQqw==
   dependencies:
     "@types/react" "*"
 
-"@types/react-dom@16.9.2":
-  version "16.9.2"
-  resolved "https://registry.yarnpkg.com/@types/react-dom/-/react-dom-16.9.2.tgz#90f9e6c161850be1feb31d2f448121be2a4f3b47"
-  integrity sha512-hgPbBoI1aTSTvZwo8HYw35UaTldW6n2ETLvHAcfcg1FaOuBV3olmyCe5eMpx2WybWMBPv0MdU2t5GOcQhP+3zA==
-  dependencies:
-    "@types/react" "*"
-
 "@types/react-native@^0.60.21":
   version "0.60.24"
   resolved "https://registry.yarnpkg.com/@types/react-native/-/react-native-0.60.24.tgz#0648aff3a910f29b8a892cecd0ec3199697bd31f"