Harmonize CI & files (#31) #39

Job	Run time
Tests / Fetch supported versions	5s
Tests / Static analysis	25s
Tests / Up to date versions	7m 0s
Tests / Late migration - PHP	22s
Tests / Up to date versions - Special case - Symfony 5.4	5m 40s
Tests / Late migration - Symfony	3m 32s
Tests / Bare minimum	14s
Tests / Bare minimum - Special case - Symfony 5.4	35s
Tests / Nightly - Symfony - With highest supported PHP version	12s
Tests / Nightly - Symfony - With lowest supported PHP version	10s
Tests / Nightly - PHP - With lowest supported Symfony versions	15s
Tests / Nightly - PHP - With highest supported Symfony versions	16s
	18m 46s

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