Bump @types/react from 16.8.23 to 16.9.4 in /app (#215)

Bumps [@types/react](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/react) from 16.8.23 to 16.9.4.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/react)

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

app/package.json

@@ -59,7 +59,7 @@
     "@types/get-value": "^3.0.1",
     "@types/node": "^12.7.8",
     "@types/prismjs": "^1.9.1",
-    "@types/react": "^16.8.23",
+    "@types/react": "^16.9.4",
     "@types/react-dom": "^16.0.11",
     "@types/react-redux": "^7.0.9",
     "@types/react-resize-detector": "^4.0.1",

app/yarn.lock

@@ -421,10 +421,10 @@
   dependencies:
     "@types/react" "*"
 
-"@types/react@*", "@types/react@^16.8.23":
-  version "16.8.23"
-  resolved "https://registry.yarnpkg.com/@types/react/-/react-16.8.23.tgz#ec6be3ceed6353a20948169b6cb4c97b65b97ad2"
-  integrity sha512-abkEOIeljniUN9qB5onp++g0EY38h7atnDHxwKUFz1r3VH1+yG1OKi2sNPTyObL40goBmfKFpdii2lEzwLX1cA==
+"@types/react@*", "@types/react@^16.9.4":
+  version "16.9.4"
+  resolved "https://registry.yarnpkg.com/@types/react/-/react-16.9.4.tgz#de8cf5e5e2838659fb78fa93181078469eeb19fc"
+  integrity sha512-ItGNmJvQ0IvWt8rbk5PLdpdQhvBVxAaXI9hDlx7UMd8Ie1iMIuwMNiKeTfmVN517CdplpyXvA22X4zm4jGGZnw==
   dependencies:
     "@types/prop-types" "*"
     csstype "^2.2.0"