Due to the vagaries of matrix handling in GHA, since #187 this could be a bit awkward.
It could make sense to add this as an extra, scheduled action, more like lockfiles.
But equally, this could be a another special case for the tests action,
given the unlikelihood of Iris breaking us (i.e. it wouldn't often block a lot of ongoing PRs)
Due to the vagaries of matrix handling in GHA, since #187 this could be a bit awkward.
It could make sense to add this as an extra, scheduled action, more like lockfiles.
But equally, this could be a another special case for the tests action,
given the unlikelihood of Iris breaking us (i.e. it wouldn't often block a lot of ongoing PRs)