Add Symfony 7 support #179

Job	Run time
Composer lockfile integrity	16s
Code standards	27s
Tests (Symfony 5.4 & PHP 7.4)	32s
Tests (Symfony 5.4 & PHP 8.0)	23s
Tests (Symfony 6.0 & PHP 8.0)	26s
Tests (Symfony 5.4 & PHP 8.1)	25s
Tests (Symfony 6.0 & PHP 8.1)	24s
Tests (Symfony 6.1 & PHP 8.1)	28s
Tests (Symfony 6.2 & PHP 8.1)	29s
Tests (Symfony 6.3 & PHP 8.1)	34s
Tests (Symfony 6.4 & PHP 8.1)	34s
Tests (Symfony 5.4 & PHP 8.2)	50s
Tests (Symfony 6.0 & PHP 8.2)	25s
Tests (Symfony 6.1 & PHP 8.2)	34s
Tests (Symfony 6.2 & PHP 8.2)	34s
Tests (Symfony 6.3 & PHP 8.2)	42s
Tests (Symfony 6.4 & PHP 8.2)	32s
Tests (Symfony 7.0 & PHP 8.2)	29s
Tests (Symfony 5.4 & PHP 8.3)	21s
Tests (Symfony 6.0 & PHP 8.3)	22s
Tests (Symfony 6.1 & PHP 8.3)	28s
Tests (Symfony 6.2 & PHP 8.3)	32s
Tests (Symfony 6.3 & PHP 8.3)	22s
Tests (Symfony 6.4 & PHP 8.3)	19s
Tests (Symfony 7.0 & PHP 8.3)	22s
Tests (Symfony 5.4 & PHP 8.1)	25s
	12m 15s

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