Pin xgboost for FLAML (#12432)

Signed-off-by: harupy <[email protected]>

.github/workflows/recipe.yml

@@ -48,7 +48,8 @@ jobs:
       - name: Install dependencies
         run: |
           source ./dev/install-common-deps.sh
-          pip install pyspark
+          # FLAML is incompatible with xgboost 2.1.0: https://github.com/microsoft/FLAML/issues/1314
+          pip install pyspark 'xgboost<2.1.0'
       - name: Run tests
         run: |
           pytest tests/recipes
@@ -74,7 +75,8 @@ jobs:
           pip install -r requirements/test-requirements.txt
           pip install --no-dependencies tests/resources/mlflow-test-plugin
           pip install .
-          pip install pyspark
+          # FLAML is incompatible with xgboost 2.1.0: https://github.com/microsoft/FLAML/issues/1314
+          pip install pyspark 'xgboost<2.1.0'
           # TODO: Importing datasets in a pandas UDF (created by mlflow.pyfunc.spark_udf) crashes
           # the Python worker. To avoid this, uninstall `datasets`. This is a temporary workaround.
           pip uninstall -y datasets