Revert "python3Packages.dataset: use sqlalchemy_1_4"

This reverts commit 3ef0b7d549 because
only unversioned attributes may be included in dependencies.

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

@@ -6,7 +6,7 @@
   buildPythonPackage,
   fetchFromGitHub,
   pythonOlder,
-  sqlalchemy_1_4,
+  sqlalchemy,
 }:
 
 buildPythonPackage rec {
@@ -28,11 +28,9 @@ buildPythonPackage rec {
   ];
 
   dependencies = [
-    (alembic.override { sqlalchemy = sqlalchemy_1_4; })
+    alembic
     banal
-    # SQLAlchemy >= 2.0.0 is unsupported
-    # https://github.com/pudo/dataset/issues/411
-    sqlalchemy_1_4
+    sqlalchemy
   ];
 
   # checks attempt to import nonexistent module 'test.test' and fail
@@ -45,5 +43,8 @@ buildPythonPackage rec {
     homepage = "https://dataset.readthedocs.io";
     license = lib.licenses.mit;
     maintainers = with lib.maintainers; [ xfnw ];
+    # SQLAlchemy >= 2.0.0 is unsupported
+    # https://github.com/pudo/dataset/issues/411
+    broken = true;
   };
 }