Add version info to mne-bids-pipeline

[larsoner]

it would be helpful if the version of the bids-pipeline used per step was to be found in the output for reporting in a paper and replicability

Originally posted by @SophieHerbst in #609 (comment)

[larsoner]

... I thought at some point we had mne.sys_info() output in there, but looking online I don't see it e.g. here

https://mne.tools/mne-bids-pipeline/1.2/examples/ds004229/sub-102_task-amnoise_report.html

We should lru_cache the output string

[hoechenberger]

... I thought at some point we had mne.sys_info() output in there, but looking online I don't see it e.g. here

It probably got lost somewhere during a refactoring, it used to be included.

But I don't think mne-bids-pipeline is listed in mne.sys_info(), or is it? If it isn't, we should add it upstream