Widen numpy requirement

[paulf81]

Widen numpy requirement

Since raising numpy requirement to 2.0 in the develop branch of FLORIS in #1051 , have noted local FLORIS/FLASC workflows are difficult with main FLORIS supporting 1.0 and develop supporting 2.0. Each virtual environment needs a little manual editing to come to a workable state when working with develop branches.

This made me think a gentler transition allows both 1 and 2 for one version iteration (or at least on develop) and that's what this PR does.

Notes:

1. The branch does not put in an open-ended >, such that the problem identified in Potential need to update numpy version to 2.0 #1030 (comment) is repeated
2. I confirm tests pass with numpy 1.20 reinstalled since Update numpy req to 2 #1051 doesn't change the code
3. The softer requirement for one version might be gentler for users, allowing the upgrade to numpy 2 while not requiring it immediately

[paulf81]

I should note also acceptable to me would to merge this into develop, and then double back and force the requirement back to 2 right before merging to main, it's just the develop/main split that's making my workflows difficult.