python3Packages.qasm2image: mark broken

Reasons: Last update was Oct 2018 (no activity on GitHub since), failed
tests don't error out the build (i.e. failed build can still succeed),
and this package has not been kept updated to reflect the changing
python3Packages.qiskit API.

pkgs/development/python-modules/qasm2image/default.nix

@@ -48,5 +48,6 @@ buildPythonPackage {
     maintainers = with lib.maintainers; [
       pandaman
     ];
+    broken = true;  # last update Oct 2018, failed tests don't error the build, and out-of-date with latest python3Packages.qiskit
   };
 }