Patch release 4.7.2

[chyunsu3]

Pull requests

• [4.7.2] Restore support for Python 3.8 #701
• [backport] Update export_model(): Add split_kind field (#698) #700. Needed for compatibility with scikit-learn 1.10.0.dev0
• [backport] [CI] Various CI fixes (#694) #702

Release Process

• Check out the latest release_4.7 branch of Treelite on a local machine.
• Create a new branch on top of release_4.7 and switch to it: git switch -c make_4.7.2.
• Create a new commit to bump the version to 4.7.2. The change should be generated by running python dev/change_version.py --major 4 --minor 7 --patch 2.
• Push the updated make_4.7.2 branch to GitHub and create a pull request. The pull request should target the release_4.7 branch. Patch release 4.7.2 #703
• Check that the CI pipeline runs successfully with the pull request.
• Merge the pull request and let the CI run. Make sure that all tests are passing and build artifacts are available at the treelite-wheels S3 bucket.
• Assign the git tag 4.7.2 to the latest commit of branch release_4.7: git checkout release_4.7 && git pull origin release_4.7 && git tag 4.7.2
• Publish the tag to GitHub: git push origin 4.7.2.
• Run the Python script dev/prepare_pypi_release.py to download the artifacts from the S3 bucket.
• Upload the artifacts to PyPI.
• Create a new release on GitHub using the tag 4.7.2.
• Submit a pull request to conda-forge/treelite-feedstock to publish the 4.7.2 release to Conda-Forge. Bump version to 4.7.2 conda-forge/treelite-feedstock#99