Switch to using Launchpad 0.4.1 which has a multi-threading fix for Python 3.9
Switch to using Launchpad 0.4.1 which has a multi-threading fix for Python 3.9

PiperOrigin-RevId: 420035626
Change-Id: Ie594d6af47e1f71ff3135a87d38ee895fc460e84

deepmind/acme,deepmind/acme