Be more verbose in changelog and upload to unstable

debian/changelog

@@ -2,6 +2,8 @@ debian-junior (1.20) unstable; urgency=low
 
   * config/control: Depends: blends-common (>= 0.6.15)
   * debian/control.stub: Build-Depends-Indep: blends-dev (>= 0.6.15)
+    which provides postrm / preinst scripts for each metapackage to
+    enable handling failed-upgrade
     Closes: #577062
   * Standards-Version: 3.9.1 (no changes needed)