Set upstream metadata fields: Security-Contact.

Changes-By: lintian-brush

debian/changelog

@@ -2,6 +2,7 @@ dulwich (0.20.26-1) UNRELEASED; urgency=low
 
   * New upstream release.
   * Bump debhelper from old 12 to 13.
+  * Set upstream metadata fields: Security-Contact.
 
  -- Jelmer Vernooij <jelmer@debian.org>  Fri, 29 Oct 2021 01:42:53 -0000
 

debian/upstream/metadata

@@ -2,3 +2,4 @@ Repository: https://github.com/dulwich/dulwich.git
 Repository-Browse: https://github.com/dulwich/dulwich
 Bug-Database: https://github.com/dulwich/dulwich/issues
 Bug-Submit: https://github.com/dulwich/dulwich/issues/new
+Security-Contact: https://github.com/dulwich/dulwich/tree/HEAD/SECURITY.md