Revert "python: breezy: 3.0.2 -> 3.1.0"

This reverts commit 89437751f958b32123f5593a7268da5e40de0e80.

Build adds more dependencies

pkgs/development/python-modules/breezy/default.nix

···
 
 buildPythonPackage rec {
   pname = "breezy";
-  version = "3.1.0";
+  version = "3.0.2";
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "1eff207403f48898fa3b3ffa7a4275197c6c58fec105ef267caf1f5fd5a6c7be";
+    sha256 = "50f16bc7faf299f98fe58573da55b0664078f94b1a0e7f0ce9e1e6a0d47e68e0";
   };
 
   propagatedBuildInputs = [ configobj six fastimport dulwich launchpadlib ];