Bug#988911: regression: claims that udebs require a Standards-Version header

[Philip Hands <phil@hands.com>]

Package: lintian
Version: 2.104.0
Severity: normal

Dear Maintainer,

Running lintian from bullseye on udebs (which do not need to have a
Standards-Version header) results in lintian throwing an error. e.g.:

  E: partman-basicmethods source: required-field debian/control@source Standards-Version
  E: partman-basicmethods source: required-field partman-basicmethods_72.dsc Standards-Version

This was not the case with 2.15.0 (from buster)

Having bisected lintian's git repo, it seems that the change in behaviour was
introduced by commit:

  54a3c2437eadb0684f6762a81a82163f36562d3e

Cheers, Phil.