The update command should always update to the next major version of the components

There's no real reason for the update:lightning command to keep you on the current major version of the components. In fact, it will make less work for site owners, since they won't have to think about changing constraints in composer.json. So let's just always require the new major versions of the components.

Additionally:

• The generated composer update command should limit the scope to drupal/lightning_* packages.
• The generated composer require command should have the --no-update flag, not --with-all-dependencies.
• The update:lightning command should error out if there are any pending database updates for Lightning extensions.