Add missing dependency on dulwich for tests

debian/changelog

+swh-model (0.0.49-1~swh2) unstable-swh; urgency=medium
+
+  * Add missing dependency on dulwich for tests
+
+ -- Nicolas Dandrimont <olasd@debian.org>  Wed, 23 Oct 2019 14:37:45 +0200
+
 swh-model (0.0.49-1~swh1) unstable-swh; urgency=medium
 
   * New upstream release 0.0.49     - (tagged by Nicolas Dandrimont

debian/control

@@ -8,6 +8,7 @@ Build-Depends: debhelper (>= 9),
                python3-all,
                python3-attr,
                python3-click,
+               python3-dulwich,
                python3-hypothesis,
                python3-pytest,
                python3-setuptools,