What does this PR do?

Unblocks CI on master. Pygame is not installed but required for running doctests in pl_examples/domain_examples/reinforce_learn_Qnet.py

Fixes #12009

Does your PR introduce any breaking changes? If yes, please list them.

I would never do that!

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Did you have fun?

I made sure I had fun coding 🙃

cc @Borda @carmocca @akihironitta