Issue #3490954 by nexusnovaz, mstrelan: Add return types to hook_update_N implementations

core/.phpstan-baseline.php

core/modules/locale/locale.install

...les/entity_test/update/entity_definition_updates_8001.inc

...les/entity_test/update/entity_definition_updates_8002.inc

...m/tests/modules/entity_test/update/status_report_8001.inc

...m/tests/modules/entity_test/update/status_report_8002.inc

...les/equivalent_update_test/equivalent_update_test.install

...s/modules/new_dependency_test/new_dependency_test.install

...sts/modules/update_script_test/update_script_test.install