Automatically collate process versions

[nh13]

Frequently in nf-core, we create a ch_versions where we mix in the version from every process in the workflow. It is tedious to maintain, and in some cases we forget to mix in. It'd would be nice if nextflow inspected every run process for a named output called versions and created a yaml with the versions at the end of the workflow. This would remove a lot of boilerplate needed for reporting software versions. Thoughts?

[bentsherman]

This is precisely what topic channels are for. They've been around for a while but nf-core has been slow to adopt. See nf-core/fetchngs#347 for a real example

[nh13]

That’s exactly it, sorry I didn’t see it earlier.