Update to commit from contrib 8.x-2.x...

core/misc/cspell/dictionary.txt

...ckage_manager/config/install/package_manager.settings.yml

.../package_manager/config/schema/package_manager.schema.yml

core/modules/package_manager/core_packages.json

core/modules/package_manager/package_manager.info.yml

core/modules/package_manager/package_manager.install

core/modules/package_manager/package_manager.services.yml

core/modules/package_manager/src/ComposerUtility.php

.../modules/package_manager/src/Event/ExcludedPathsTrait.php

core/modules/package_manager/src/Event/PostApplyEvent.php

core/modules/package_manager/src/Event/PostCreateEvent.php

core/modules/package_manager/src/Event/PostDestroyEvent.php

core/modules/package_manager/src/Event/PostRequireEvent.php

core/modules/package_manager/src/Event/PreApplyEvent.php

core/modules/package_manager/src/Event/PreCreateEvent.php

core/modules/package_manager/src/Event/PreDestroyEvent.php

...ules/package_manager/src/Event/PreOperationStageEvent.php

core/modules/package_manager/src/Event/PreRequireEvent.php

core/modules/package_manager/src/Event/StageEvent.php

...nager/src/EventSubscriber/ComposerExecutableValidator.php