Plugin fails when files owned by another user

[zaporylie]

chmod() returns error if files are owned by another user than one triggering composer command. That makes all file disappear (moved to composer cache folder) and never restored.

Maybe we should test if we can perform chmod() operation and fail early with information what have happened.

Ref.

preserve-paths/src/PathPreserver.php

Line 256 in 7f99622

chmod($path, static::FILEPERM);