Set upstream metadata fields: Repository, Repository-Browse.

Changes-By: lintian-brush
Fixes: lintian: upstream-metadata-file-is-missing
See-also: https://lintian.debian.org/tags/upstream-metadata-file-is-missing.html
Fixes: lintian: upstream-metadata-missing-repository
See-also: https://lintian.debian.org/tags/upstream-metadata-missing-repository.html