ci: update PHPCS dev branch from master to 3.x #398

Job	Run time
QTest + Lint: PHP latest - PHPCS stable	17s
QTest: PHP latest - PHPCS lowest	23s
QTest + Lint: PHP 5.4 - PHPCS stable	53s
QTest: PHP 5.4 - PHPCS lowest	1m 7s
	2m 40s

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