dpkg: upgrade to v1.21.22

  * Code internals:
    - libdpkg: Handle missing Version when formatting source:Upstream-Version.
      Reported by John Scott <email address hidden>.
  * Localization:
    - Add Portuguese scripts translations.
      Thanks to Américo Monteiro <email address hidden>. Closes: #1032562

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
(cherry picked from commit 56bdf69a)
Signed-off-by: Steve Sakoman <steve@sakoman.com>