Table of contents:
aptly package search 'Name (% postgresql-13)'
Check out possible query params.
aptly package show -with-files -with-references postgresql-13_13.5-1.pgdg100+1_amd64
aptly repo add $REPO_NAME /package/location/wherever/it/is/postgresql-13_13.5-1.pgdg100+1_amd64.deb