try fix CI: pin coremltools 8.0b2

Author: yifan_shen3

backends/apple/coreml/scripts/install_requirements.sh

@@ -24,7 +24,7 @@ rm -rf "$COREML_DIR_PATH/third-party"
 mkdir "$COREML_DIR_PATH/third-party"
 
 echo "${green}ExecuTorch: Cloning coremltools."
-git clone --depth 1 --branch 8.0b1 "https://github.com/apple/coremltools.git" $COREMLTOOLS_DIR_PATH
+git clone --depth 1 --branch 8.0b2 "https://github.com/apple/coremltools.git" $COREMLTOOLS_DIR_PATH
 cd $COREMLTOOLS_DIR_PATH
 
 STATUS=$?

backends/apple/coreml/test/test_coreml_partitioner.py

@@ -91,10 +91,6 @@ def test_vit_skip_conv(self):
             if node.op == "call_function"
         ] == total
 
-    @pytest.mark.skipif(
-        "b" in ct.__version__ or ct.__version__ < "8.0",
-        reason="coremltools 8.0 or higher is required",
-    )
     def test_buffer(self):
         embedding_dim = 3
         max_seq_len = 2