Limit `ExponentialBackoff` to specifying just `$backoff` #51

Job	Run time
Fix PHP codestyle with php-cs-fixer	13s
Normalize composer.json	24s
Validate composer dependencies	6s
Code Coverage	46s
PHPStan on PHP 8.1 with Laravel ^9.51	17s
Tests - PHP 8.1, Illuminate , lowest	48s
PHPStan on PHP 8.1 with Laravel ^10	17s
Tests - PHP 8.1, Illuminate , lowest	47s
PHPStan on PHP 8.2 with Laravel ^9.51	18s
Tests - PHP 8.1, Illuminate , highest	35s
PHPStan on PHP 8.2 with Laravel ^10	17s
Tests - PHP 8.1, Illuminate , highest	35s
PHPStan on PHP 8.3 with Laravel ^9.51	22s
Tests - PHP 8.2, Illuminate , lowest	39s
PHPStan on PHP 8.3 with Laravel ^10	24s
Tests - PHP 8.2, Illuminate , lowest	37s
Tests - PHP 8.2, Illuminate , highest	45s
Tests - PHP 8.2, Illuminate , highest	43s
Tests - PHP 8.3, Illuminate , lowest	40s
Tests - PHP 8.3, Illuminate , lowest	39s
Tests - PHP 8.3, Illuminate , highest	42s
Tests - PHP 8.3, Illuminate , highest	41s
	11m 35s

Provide feedback