Updated phpstan to v2.1 (#4430) #5

Job	Run time
Debug	1s
Check files / Changed	11s
Composer / Validation	8s
XML Syntax / XML Validation	27s
Code-QL / Analyze (javascript)	1m 18s
PHPMD / Mess Detector	5m 48s
PHPStan / Analyze (ubuntu-latest, 7.4)	5m 43s
PHP CS Fixer / Validation	3m 10s
PHP CS / Validation	8m 19s
PHPStan / Analyze (ubuntu-latest, 8.4)	3m 2s
PHP Syntax	0s
Rector / Rector	6m 25s
Unit Tests (OpenMage) / unit-tests (ubuntu-latest, 7.4, 5.7)	1m 43s
Unit Tests (OpenMage) / unit-tests (ubuntu-latest, 7.4, 8.0)	1m 47s
Unit Tests (OpenMage) / unit-tests (ubuntu-latest, 8.3, 5.7)	1m 48s
Unit Tests (OpenMage) / unit-tests (ubuntu-latest, 8.3, 8.0)	1m 52s
	41m 42s

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