Unpin numpy <2

[oysteinequinor]

Numpy 2.0 has now been released and xtgeo is blocking the update for dependents due to pinning.

Issue where it was pinned: #878

[mferrera]

We may be a bit logjammed on this for some time due to numpy being similarly pinned a few dependencies down.

resfo 4.1.0 requires numpy<2, but you have numpy 2.0.0 which is incompatible.
ecl-data-io 3.1.1 requires numpy<2, but you have numpy 2.0.0 which is incompatible.
xtgeoviz 0.1.0 requires numpy<2, but you have numpy 2.0.0 which is incompatible.
roffio 1.0.2 requires numpy<2, but you have numpy 2.0.0 which is incompatible.

[larsevj]

The latest versions of resfo and roffio now supports numpy 2.

[mferrera]

A consequence of supporting numpy 2 is that we have to drop support for Python 3.8. So although I have a PR that does it open we may end up postponing it until October.