Revert "Merge pull request #256497 from NickCao/python-msgpack"

This reverts commit 378fbaff985bb69424db700f0ec67aad8f83ad6f, reversing
changes made to 4b786de439279a1b09b2ba3256770d71b2698835.

As they caused breakage for borgbackup which is quite a ubiquitious
software for backupping and stopping all updates on the
nixos-unstable-small channel as it is hard to remove such software from
your configuration.

Thankfully, 1.0.6 and 1.0.7 changelog:

https://github.com/msgpack/msgpack-python/releases/tag/v1.0.6
https://github.com/msgpack/msgpack-python/releases/tag/v1.0.7

are not security updates, this should not cause issues.

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

···
 { lib
 , buildPythonPackage
-, fetchFromGitHub
+, fetchPypi
 , pytestCheckHook
 , pythonOlder
 , setuptools
-, cython_3
 }:
 
 buildPythonPackage rec {
   pname = "msgpack";
-  version = "1.0.7";
-  pyproject = true;
+  version = "1.0.5";
+  format = "setuptools";
 
-  disabled = pythonOlder "3.8";
+  disabled = pythonOlder "3.6";
 
-  src = fetchFromGitHub {
-    owner = "msgpack";
-    repo = "msgpack-python";
-    rev = "refs/tags/v${version}";
-    hash = "sha256-ayEyvKiTYPdhy4puUjtyGIR+jsTXd2HRINaAYxQGTZM=";
+  src = fetchPypi {
+    inherit pname version;
+    hash = "sha256-wHVUQoTq3Fzdxw9HVzMdmdy8FrK71ISdFfiq5M820xw=";
   };
 
   nativeBuildInputs = [
     setuptools
-    cython_3
   ];
 
   nativeCheckInputs = [