Update mockito-core to 5.6.0 #1898

Job	Run time
conformance	1m 51s
build (2_12, mima)	1m 27s
build (2_12, e2e)	4s
build (2_12, test)	14m 17s
build (2_13, mima)	1m 42s
build (2_13, e2e)	4s
build (2_13, test)	15m 2s
build (3, mima)	7s
build (3, e2e)	8s
build (3, test)	8m 4s
build (2_12, examples_and_formatting)	3m 19s
build (2_13, scala3_compat_test)	11m 6s
build (3, scala3_compat_test)	12m 59s
ci-passed	1s
	1h 10m 11s

Provide feedback