Add CI runner to check we can compile with older cmake versions

[Luthaf]

We had a report that the code fails to compile with cmake 3.23, which is not ideal. It would be nice to make sure we can compile the code on older cmake, idealy cmake 3.16 like metatensor/rascaline (this is the version on Debian stable).

[ceriottm]

Living on the edge. Will only compile with cmake_nightly.