mailman: fix build

Required an update to the sqlalchemy override due to new hash variable
usage. Also disables tests for sqlalchemy and alembic because neither
can find any, so they error out.

pkgs/servers/mail/mailman/default.nix

@@ -5,12 +5,18 @@ let
   # Mailman does not support sqlalchemy >= 1.4 https://gitlab.com/mailman/mailman/-/issues/845
   pythonOverride = python3.override {
     packageOverrides = self: super: {
+      alembic = super.alembic.overridePythonAttrs (oldAttrs:  {
+        # does not find tests
+        doCheck = false;
+      });
       sqlalchemy = super.sqlalchemy.overridePythonAttrs (oldAttrs: rec {
         version = "1.3.24";
         src = oldAttrs.src.override {
           inherit version;
-          sha256 = "06bmxzssc66cblk1hamskyv5q3xf1nh1py3vi6dka4lkpxy7gfzb";
+          hash = "sha256-67t3fL+TEjWbiXv4G6ANrg9ctp+6KhgmXcwYpvXvdRk=";
         };
+        # does not find tests
+        doCheck = false;
       });
     };
   };