Updating component usage to use composer require

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3+
| Fixed tickets | n/a

Hi guys!

This shows using the new `composer require` command instead of manually updating `composer.json`. It shortens and simplifies things quite a bit :grinning: 

Thanks!
On the other hand, it'll be quicker... (we do this in the tests of the CMF for instance, while we never use everything in our tests)