Update CI to use latest versions of pyarrow and numpy. Drop pyarrow 4 test config.

Does not seem to be anything special in pyarrow 4, so dropped it.

Author: Yevgeni Litvin

.github/workflows/unittest.yml

@@ -47,18 +47,11 @@ jobs:
           PYSPARK_VERSION: "3.0.0"
           ARROW_PRE_0_15_IPC_FORMAT: 0
           PY: "3.7"
-        - config: pyarrow-4.0
-          PYARROW_VERSION: "4.0.0"
-          NUMPY_VERSION: "1.19.1"
-          TF_VERSION: "2.5.0"
-          PYSPARK_VERSION: "3.0.0"
-          ARROW_PRE_0_15_IPC_FORMAT: 0
-          PY: "3.7"
         - config: latest
-          PYARROW_VERSION: "6.0.1"
-          NUMPY_VERSION: "1.21.5"
-          TF_VERSION: "2.8.0"
-          PYSPARK_VERSION: "3.0.0"
+          PYARROW_VERSION: "9.0.0"
+          NUMPY_VERSION: "1.21.6"
+          TF_VERSION: "2.10.0"
+          PYSPARK_VERSION: "3.3.0"
           ARROW_PRE_0_15_IPC_FORMAT: "0"
           PY: "3.9"