Add action that tests against older versions of msprime etc?

[jeromekelleher]

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#1067 was a good reminder that there are unexpected consequences of changing things and there's actually quite a lot of software out there that needs to stay working when tskit get updated.

So, how about we add a Github action that installs a few versions of some of the main bits of downstream software, and we check that they basically work?

The action would basically be:

pip install .
pip install msprime==0.7.4
msp simulate 10 tmp.trees
tskit info tmp.trees

Doing this for a handful of msprime versions (in a matrix?) would be a good test. We could also do something simular for tsinfer, I guess?

[benjeffery]

Sounds like a good idea.

[jeromekelleher]

No hurry with it - probably good for me to do so I have some idea how GitHub actions work!