Add PHP 8 attributes support #16

Job	Run time
Run tests PHP 7.1 Symfony 3.* highest	1m 43s
Run tests PHP 7.1 Symfony 4.* highest	1m 44s
Run tests PHP 7.2 Symfony 3.* highest	1m 40s
Run tests PHP 7.2 Symfony 4.* highest	1m 41s
Run tests PHP 7.2 Symfony 5.* highest	2m 9s
Run tests PHP 7.3 Symfony 3.* highest	1m 34s
Run tests PHP 7.3 Symfony 4.* highest	1m 41s
Run tests PHP 7.3 Symfony 5.* highest	1m 47s
Run tests PHP 7.4 Symfony 3.* highest	1m 47s
Run tests PHP 7.4 Symfony 4.* highest	1m 16s
Run tests PHP 7.4 Symfony 5.* highest	1m 42s
Run tests PHP 8.0 Symfony 4.* highest	1m 29s
Run tests PHP 8.0 Symfony 5.* highest	1m 45s
Run tests PHP 8.1 Symfony 4.* highest	1m 36s
Run tests PHP 8.1 Symfony 5.* highest	1m 47s
Run tests PHP 8.1 Symfony 6.* highest	2m 5s
Run tests PHP 8.2 Symfony 4.* highest	1m 32s
Run tests PHP 8.2 Symfony 5.* highest	1m 44s
Run tests PHP 8.2 Symfony 6.* highest	2m 28s
Run tests PHP 7.1 Symfony 3.* lowest	1m 36s
	34m 46s

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