reduce code duplication

[KiaraGrouwstra]

i tried yaml anchors, but github actions doesn't support them.
what other options are there?
i considered maybe just iterating over a list of repos, but i guess that'd require multiple lists as i didn't manage to do dynamic secrets within a step (can be defined from env but that doesn't allow for much prior logic).
an alternative might be composite actions but this seems overkill if it's gotta go thru marketplace instead of working from the same file.

[KiaraGrouwstra]

github action install ssh key may help