Update Lazy-load module documentation to reflect latest module and lazysizes library versions

The current Composer installation example on the Lazy-load module documentation page uses outdated version constraints:

drupal/lazy:^3.0 — the latest stable release is 4.0.

bower-asset/lazysizes:^5.1 — the latest available version is 5.3.2.

Using outdated constraints could:

Prevent users from accessing new features, security patches, or bug fixes.

Cause confusion when trying to install or integrate the latest version.

Introduce conflicts if newer versions are required elsewhere in a project.

Proposed Update: Update the documentation to the latest supported versions.

Update this:

composer require drupal/lazy:^3.0 bower-asset/lazysizes:^5.1 oomphinc/composer-installers-extender:^2.0 --no-update

To:

composer require drupal/lazy:^4.0 bower-asset/lazysizes:^5.3 oomphinc/composer-installers-extender:^2.0 --no-update

Update composer.json example:

"require": {
  "drupal/lazy": "^4.0",
  "bower-asset/lazysizes": "^5.3",
  "oomphinc/composer-installers-extender": "^2.0"
}