[8.x] syncWithPivotDefaults method

[ddzobov]

This PR introduces ability to sync records with default values in pivot tables

$server = Server::find(1);
$ips = Ip::findMany([1,2,3]);

$server->ips()->syncWithPivotDefaults($ips, ['vlan' => 1444]);

[ddzobov]

something wrong with tests, it fails not on my changes

[driesvints]

@ddzobov I'm looking into that now. Feel free to ignore

[taylorotwell]

How is this different than sync? Just so you don't have to pass the pivot attributes with each key?

[ddzobov]

How is this different than sync? Just so you don't have to pass the pivot attributes with each key?

If i want to do this via sync method, it will be something like this:

$server = Server::find(1);
$ips = Ip::findMany([1,2,3]);

$server->ips()->sync([
     1 => ['vlan' => 1444],
     2 => ['vlan' => 1444],
     3 => ['vlan' => 1444],
]);

// or
$defaults = ['vlan' => 1444];
$server->ips()->sync(
     $ips->mapWithKeys(fn($item) => [$item->getKey() => $defaults])->all()
);