Update numpy req to 2

[paulf81]

Update numpy req to 2

Testing an update based on #1030 where the numpy requirement is pushed up to compatiable version of 2.0.

An alternative approach would be to span version 1 and 2 using > and < operators, but I understand this to be non-preferred in semantic versioning, since testing would only apply to newer major version, and so the previous major version is not truly supported.

Using this PR also to check if having the requirement at ~=2.0 raises any incompatibilities.

Related issue

#1030

[misi9170]

I'm OK with going up to ~=2.0. We'll also be dropping support for python 3.8 in the next minor FLORIS version #1042 , and this feels like a similar thing. However, there are likely to be users that will still be on numpy 1.x, who may be prevented from upgrading to FLORIS 4.3 if we introduce this requirement.