d/control: add breaks on packages depending on removed APIs

debian/control

@@ -4,10 +4,10 @@ Section: python
 Priority: optional
 Build-Depends: debhelper (>= 9),
                dh-python,
+               python3 (>= 3.5) | python3-pyblake2,
                python3-all,
                python3-nose,
                python3-setuptools,
-               python3 (>= 3.5) | python3-pyblake2,
                python3-vcversioner
 Standards-Version: 3.9.6
 Homepage: https://forge.softwareheritage.org/diffusion/DMOD/
@@ -15,4 +15,7 @@ Homepage: https://forge.softwareheritage.org/diffusion/DMOD/
 Package: python3-swh.model
 Architecture: all
 Depends: ${misc:Depends}, ${python3:Depends}
+Breaks: python3-swh.loader.core (<< 0.0.16~),
+        python3-swh.loader.dir (<< 0.0.28~),
+        python3-swh.loader.svn (<< 0.0.28~)
 Description: Software Heritage data model