artifact upload failure with multiple patterns

[francesco-ballarin]

Artifact upload with more than one pattern (e.g. *.ipynb for notebook_pattern, and *.dat for extra_files_pattern) currently doesn't upload anything, and gives the warning

Warning: No files were found with the provided path: open_in_colab/**/*.ipynb%0Aopen_in_colab/**/*.dat. No artifacts will be uploaded.

This is due to recent changes in actions/upload-artifact not correctly escaping multiple patterns when reading path from GITHUB_OUTPUT. The issue has been reported upstream at actions/upload-artifact#394