macos x86 run notebook tests use python 3.9 (#413)

Author: kafka1991

.github/workflows/build_macos_x86_wheels.yml

@@ -281,7 +281,7 @@ jobs:
         run: |
           export PATH="$HOME/.pyenv/bin:$PATH"
           eval "$(pyenv init -)"
-          pyenv shell 3.8
+          pyenv shell 3.9
           python -m pip install dist/*.whl --force-reinstall
           jupyter nbconvert --to notebook --execute tests/test_data_insertion.ipynb --output test_data_insertion_output.ipynb
           pyenv shell --unset