[RLlib] Pin ALE-py In Rllib Requirements And Other Release Test Fixes

[ArturNiederfahrenhorst]

Why are these changes needed?

#28913 was merged but introduces another error: RLlib's Integration tests require gym.
Screenshot from the CI tests from that PR:

Checks

• I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[gjoliver]

I have a feeling gym shouldn't need to be in the base requirements.txt
if any integration needs gym, it should probably install the ml/rl requirements?

[ArturNiederfahrenhorst]

I have a feeling gym shouldn't need to be in the base requirements.txt if any integration needs gym, it should probably install the ml/rl requirements?

I agree. But for that we would need to move the offending tests, since we can't test integration without gym. So this should happen in the long term. This fix is merely a reference for the 2.0.1 release and maybe the short-term fix we can do for 2.1 which will be cut soon,