[docs] remove xgboost-ray and lightgbm-ray from requirements-doc.txt

[matthewdeng]

Signed-off-by: Matthew Deng matt@anyscale.com

Why are these changes needed?

Related issue number

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 :(

[matthewdeng]

Closing this - looks like these are still needed.

WARNING: autodoc: failed to import class 'xgboost.XGBoostTrainer' from module 'ray.train'; the following exception was raised:
--
  | No module named 'xgboost'
  | WARNING: autodoc: failed to import module 'xgboost' from module 'ray.train'; the following exception was raised:
  | No module named 'xgboost'
  | WARNING: autodoc: failed to import class 'lightgbm.LightGBMTrainer' from module 'ray.train'; the following exception was raised:
  | No module named 'lightgbm'
  | WARNING: autodoc: failed to import module 'lightgbm' from module 'ray.train'; the following exception was raised:
  | No module named 'lightgbm'
  | WARNING: autodoc: failed to import class 'xgboost.XGBoostTrainer' from module 'ray.train'; the following exception was raised:
  | No module named 'xgboost'
  | WARNING: autodoc: failed to import module 'xgboost' from module 'ray.train'; the following exception was raised:
  | No module named 'xgboost'
  | WARNING: autodoc: failed to import class 'lightgbm.LightGBMTrainer' from module 'ray.train'; the following exception was raised:
  | No module named 'lightgbm'
  | WARNING: autodoc: failed to import module 'lightgbm' from module 'ray.train'; the following exception was raised:
  | No module named 'lightgbm'
  | WARNING: autodoc: failed to import class 'xgboost.TuneReportCallback' from module 'ray.tune.integration'; the following exception was raised:
  | No module named 'xgboost'
  | WARNING: autodoc: failed to import class 'xgboost.TuneReportCheckpointCallback' from module 'ray.tune.integration'; the following exception was raised:
  | No module named 'xgboost'
  | WARNING: autodoc: failed to import class 'lightgbm.TuneReportCallback' from module 'ray.tune.integration'; the following exception was raised:
  | No module named 'lightgbm'
  | WARNING: autodoc: failed to import class 'lightgbm.TuneReportCheckpointCallback' from module 'ray.tune.integration'; the following exception was raised:
  | No module named 'lightgbm'