Bump react-ga from 2.7.0 to 3.3.1 in /example

Bumps [react-ga](https://github.com/react-ga/react-ga) from 2.7.0 to 3.3.1.
- [Release notes](https://github.com/react-ga/react-ga/releases)
- [Commits](react-ga/react-ga@v2.7.0...v3.3.1)

---
updated-dependencies:
- dependency-name: react-ga
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

example/package.json

@@ -16,7 +16,7 @@
     "prop-types": "^15.7.2",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",
-    "react-ga": "^2.7.0",
+    "react-ga": "^3.3.1",
     "react-redux": "^7.1.1",
     "redux": "^4.0.5",
     "redux-saga": "^1.1.3",

example/yarn.lock

@@ -4389,10 +4389,10 @@ react-dom@^16.13.1:
     prop-types "^15.6.2"
     scheduler "^0.19.1"
 
-react-ga@^2.7.0:
-  version "2.7.0"
-  resolved "https://registry.yarnpkg.com/react-ga/-/react-ga-2.7.0.tgz#24328f157f31e8cffbf4de74a3396536679d8d7c"
-  integrity sha512-AjC7UOZMvygrWTc2hKxTDvlMXEtbmA0IgJjmkhgmQQ3RkXrWR11xEagLGFGaNyaPnmg24oaIiaNPnEoftUhfXA==
+react-ga@^3.3.1:
+  version "3.3.1"
+  resolved "https://registry.yarnpkg.com/react-ga/-/react-ga-3.3.1.tgz#d8e1f4e05ec55ed6ff944dcb14b99011dfaf9504"
+  integrity sha512-4Vc0W5EvXAXUN/wWyxvsAKDLLgtJ3oLmhYYssx+YzphJpejtOst6cbIHCIyF50Fdxuf5DDKqRYny24yJ2y7GFQ==
 
 react-is@^16.6.3, react-is@^16.7.0, react-is@^16.8.1, react-is@^16.8.6, react-is@^16.9.0:
   version "16.9.0"