Github Actions node warning

[harmonbhasin]

I get the following warning from Github Actions, I should probably handle this at some point:

The following actions use a deprecated Node.js version and will be forced to run on node20: nf-core/setup-nextflow@v1. For more info: https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/