pyroaring: Override Cython version for tests/build

- `pyroaring` upstream have a constraint against `cython` v3.1.x, which
  means we need to stick to `cython` v3.0.12.
   - This is due to a few tests failing with newer `cython` versions.

- It affects `buildstream` and `python3Packages.buildstream-plugins` in
  Nixpkgs, which is why I have implemented this quick workaround to
  make `pyroaring` use a older version of `cython`.

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

@@ -21,7 +21,16 @@ buildPythonPackage rec {
   };
 
   build-system = [
-    cython
+    (cython.overrideAttrs (rec {
+      name = "cython";
+      version = "3.0.12";
+      src = fetchFromGitHub {
+        owner = "cython";
+        repo = "cython";
+        tag = version;
+        hash = "sha256-clJXjQb6rVECirKRUGX0vD5a6LILzPwNo7+6KKYs2pI=";
+      };
+    }))
     setuptools
   ];