update CI workflow to support PHP versions 8.3 and 8.4; add .phpunit.… #39

Job	Run time
Coding Standard & Static Analysis	2m 42s
testsuite (8.1, sqlite)	15s
testsuite (8.1, mysql)	24s
testsuite (8.1, pgsql)	19s
testsuite (8.2, sqlite)	22s
testsuite (8.2, mysql)	33s
testsuite (8.2, pgsql)	22s
testsuite (8.3, sqlite)	19s
testsuite (8.3, mysql)	33s
testsuite (8.3, pgsql)	29s
testsuite (8.4, sqlite)	12s
testsuite (8.4, mysql)	26s
testsuite (8.4, pgsql)	16s
	7m 12s

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