sigal: 2.3 -> 2.4

This fixes the broken build on nixpkgs 23.11/unstable, and we can drop the
permissions patch because it's included upstream.

pkgs/applications/misc/sigal/copytree-permissions.patch

@@ -1,16 +0,0 @@
-diff -Nurp sigal-2.3.orig/sigal/writer.py sigal-2.3/sigal/writer.py
---- sigal-2.3.orig/sigal/writer.py	2022-08-08 19:43:10.934707194 +0200
-+++ sigal-2.3/sigal/writer.py	2022-08-08 19:44:57.542382532 +0200
-@@ -103,7 +103,11 @@ class AbstractWriter:
-             os.path.join(THEMES_PATH, 'default', 'static'),
-             os.path.join(self.theme, 'static'),
-         ):
--            shutil.copytree(static_path, self.theme_path, dirs_exist_ok=True)
-+            # https://stackoverflow.com/a/17022146/4935114
-+            orig_copystat = shutil.copystat
-+            shutil.copystat = lambda x, y: x
-+            shutil.copytree(static_path, self.theme_path, dirs_exist_ok=True, copy_function=shutil.copy)
-+            shutil.copystat = orig_copystat
- 
-         if self.settings["user_css"]:
-             if not os.path.exists(self.settings["user_css"]):

pkgs/applications/misc/sigal/default.nix

@@ -7,15 +7,17 @@
 
 python3.pkgs.buildPythonApplication rec {
   pname = "sigal";
-  version = "2.3";
-  format = "setuptools";
+  version = "2.4";
+  pyproject = true;
 
   src = fetchPypi {
     inherit version pname;
-    hash = "sha256-4Zsb/OBtU/jV0gThEYe8bcrb+6hW+hnzQS19q1H409Q=";
+    hash = "sha256-pDTaqtqfuk7tACkyaKClTJotuVcTKli5yx1wbEM93TM=";
   };
 
-  patches = [ ./copytree-permissions.patch ];
+  nativeBuildInputs = with python3.pkgs; [
+    setuptools-scm
+  ];
 
   propagatedBuildInputs = with python3.pkgs; [
     # install_requires
@@ -31,8 +33,6 @@ python3.pkgs.buildPythonApplication rec {
     feedgenerator
     zopfli
     cryptography
-
-    setuptools # needs pkg_resources
   ];
 
   nativeCheckInputs = [