v4.0.4
[SPARK-50042][PYTHON] Upgrade numpy 2 for python linter
[SPARK-47683][PYTHON][BUILD] Decouple PySpark core API to pyspark.core package
[SPARK-46224][PYTHON][MLLIB][TESTS] Test string representation of TestResult (pyspark.mllib.stat.test)
[SPARK-37022][PYTHON] Use black as a formatter for PySpark
[SPARK-45448][PYTHON] Fix imports according to PEP8: pyspark.testing, pyspark.mllib, pyspark.resource and pyspark.streaming
[SPARK-49792][PYTHON][BUILD] Upgrade to numpy 2 for building and testing Spark branches