Adding file checksum field in SPDX documents

[lumjjb]

What would you like to be added:

According the SPDX spec, the hashes of files should be attached through the "8.4 File checksum field", https://github.com/spdx/tools-golang/blob/main/spdx/v2_2/file.go#L21-L23, right now

Why is this needed:

This is needed to help provide identifiers to files which can be used for analysis of SPDX documents.

Additional context:

[lumjjb]

hmm interesting, i see code in this (https://github.com/anchore/syft/blob/main/syft/formats/spdx22json/to_format_model.go#L157) but is not showing in the output. let me investigate..

[lumjjb]

user problem , needed to flip on the file catalogers, picking up TEXT file checksums...