Add workflow concurrency #74

Job	Run time
PHP 7.4, ubuntu-latest, prefer-lowest	22s
PHP 7.4, ubuntu-latest, prefer-stable	18s
PHP 7.4, macos-latest, prefer-lowest	1s
PHP 7.4, macos-latest, prefer-stable	1s
PHP 7.4, windows-latest, prefer-lowest	33s
PHP 7.4, windows-latest, prefer-stable	35s
PHP 8.0, ubuntu-latest, prefer-lowest	13s
PHP 8.0, ubuntu-latest, prefer-stable	13s
PHP 8.0, macos-latest, prefer-lowest	1s
PHP 8.0, macos-latest, prefer-stable	1s
PHP 8.0, windows-latest, prefer-lowest	28s
PHP 8.0, windows-latest, prefer-stable	29s
PHP 8.1, ubuntu-latest, prefer-lowest	16s
PHP 8.1, ubuntu-latest, prefer-stable	19s
PHP 8.1, macos-latest, prefer-lowest	1s
PHP 8.1, macos-latest, prefer-stable	1s
PHP 8.1, windows-latest, prefer-lowest	42s
PHP 8.1, windows-latest, prefer-stable	38s
PHP 8.2, ubuntu-latest, prefer-lowest	22s
PHP 8.2, ubuntu-latest, prefer-stable	20s
PHP 8.2, macos-latest, prefer-lowest	1s
PHP 8.2, macos-latest, prefer-stable	1s
PHP 8.2, windows-latest, prefer-lowest	28s
PHP 8.2, windows-latest, prefer-stable	31s
PHP 8.3, ubuntu-latest, prefer-lowest	18s
PHP 8.3, ubuntu-latest, prefer-stable	12s
PHP 8.3, macos-latest, prefer-lowest	1s
PHP 8.3, macos-latest, prefer-stable	1s
PHP 8.3, windows-latest, prefer-lowest	29s
PHP 8.3, windows-latest, prefer-stable	31s
	8m 27s

Provide feedback