Tests fail on new camb version

[itrharrison]

Two tests against precomputed likelihood values now fail see here, I'm pretty sure due to the bump in camb version to v1.4.

e.g.

FAILED test_clusters.py::test_clusters_loglike - assert array([False])
 +  where array([False]) = (array([-854.8981993]), -855.0)

I can just update the test against the new precomputed likelihood values, or change the tolerance on the isclose.

[itrharrison]

I can confirm that putting camb<1.4 in the requirements.txt is another option to make the tests pass. Hidde points out this is likely due to the derfault neutrino spec changing.

[cmbant]

Looks like a small change, similar to other likelihood test tweaks