New update fields for cme dpkg

Hi

I've been working to allow cme update to update more data than the copyright file.

Currently, I've added the possibility to retrieve homepage and repo url information from upstream files like META.yml. (ok, this is not huge, but it's a start).

For instance, running "cme update dpkg-upstream-metadata" would copy repository URL from dist.ini or meta.yml in debian/upstream/metadata Repository field.

This required to update Dpkg model to specify the field to update, the file type and name, and where to find the relevant information.

I've added these modifications in add_update branch of libconfig-model-dpkg-perl and opened a MR [1] so you can check the new code.

Please tell me if this useful.

If that's the case, I would welcome commits or patches to support more parameters. If you want to contribute, I strongly suggest to use "cme meta edit" in libconfig-model-dpkg-perl directory to add support for other parameters.

All the best

[1] https://salsa.debian.org/perl-team/modules/packages/libconfig-model-dpkg-perl/-/merge_requests/12