python3Packages.matrix-client: fix pname wrt PEP503 normalization

pkgs/development/python-modules/matrix-client/default.nix

···
 }:
 
 buildPythonPackage rec {
-  pname = "matrix_client";
+  pname = "matrix-client";
   version = "0.4.0";
 
   src = fetchPypi {
-    inherit pname version;
+    pname = "matrix_client";
+    inherit version;
     sha256 = "0mii7ib3bah5ppqs7i8sjv5l0zbl57011908m4l0jbyby90ayy06";
   };