src/Repositories/ManyToManyRepositoryEloquent.php
public function update(array $attributes, $id)
    {
        $defaults = ["{$this->getRelationName()}" => []];
        $attributes = array_merge($defaults, $attributes);
        $model = parent::update($attributes, $id);
        $model->{$this->getShortRelationName()}()->sync($attributes["{$this->getRelationName()}"]);
        return $this->parserResult($model);
    }
public function update(array $attributes, $id)
    {
        $defaults = ["{$this->getRelationName()}" => []];
        $attributes = array_merge($defaults, $attributes);
        $model = parent::update($attributes, $id);
        $model->{$this->getShortRelationName()}()->sync($attributes["{$this->getRelationName()}"]);
        return $this->parserResult($model);
    }
Update attributes

@param array $attributes
@param integer $id

@return Model