(dev/core#3581) composer.json - Allow newer version of oauth2-google

(dev/core#3581) composer.json - Allow newer version of oauth2-google

I looked at the diffs for v3.0.4 and 4.0.0.

* They raised the requirements to PHP 7.3/8.0 and added some type-hints.
* They raised the test-env to PHPUnit 8/9
* They updated some metadata to say all that.
* The main contracts are provided by `league/oauth2-client` -- which
  hasn't changed. It's still the same v2.x requirement.
* I don't believe that Civi directly extends/overrides any of the Google Auth stuff.