Add numpy 2.0 compatibility

[dstansby]

Fixes #521.

Currently the solution is to just test without zfpy support, which is easy to implement. In an ideaL world I guess we want to run at least one test with zfpy and numpy<2? I won't have time to implement that in the next few days, so someone else feel free to take over and do that if desirable.

[normanrz]

I think this it a good solution. I will merge tomorrow if there are no objections.

We should track numpy 2.0 support in zfpy, though.

[dstansby]

I updated this so the Python 3.10 tests use numpy<2 and zfpy, so hopefully we still get the zfpy tests running.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.91%. Comparing base (5f13152) to head (05b9edf).
Report is 29 commits behind head on main.

Additional details and impacted files

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  Coverage   99.91%   99.91%           
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  Files          59       59           
  Lines        2318     2318           
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  Hits         2316     2316           
  Misses          2        2