It sounds like the file contains structured data which could also reside in a data store.
Can the business instead come into App Studio and update this lookup list as Records of a Data Object that are stored in Pega? If kept as a file, you would need to implement some sort of integration and turn that file content into instances of classes anyway, so it would be:
Less configuration effort and less things-that-can-go-wrong if you don't need to build an integration; and
Perhaps a better maintenance experience for the business to use a Records editor than updating a file on a shared folder somewhere.