Bump phpstan to 1.12.x (#2363) #1469

Job	Run time
Windows - PHP 8.1 & SQL Server	2m 59s
Coding Standard & Static Analysis	43s
testsuite (8.1, sqlite)	38s
testsuite (8.4, mysql)	1m 2s
testsuite (8.1, pgsql)	52s
testsuite (8.4, pgsql)	49s
testsuite (8.1, sqlite, prefer-lowest)	35s
testsuite (8.1, mysql)	50s
testsuite (8.4, sqlite)	31s
testsuite (8.2, mysql)	1m 1s
	10m 0s

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