Remove restriction on numpy

[joshua-hampton]

NumPy was restricted to version 1 when version 2 came out. This restriction needs to be removed to allow checksit to continue working with more recent versions of Python, as other dependencies drop support for NumPy 1.

[joshua-hampton]

Removing the restriction on numpy from the requirements and allowing mamba to resolve dependencies, all tests passed for all Python versions from 3.7 onwards, with the following versions of each dependency (plus pytest) being used.

Python	click	pyyaml	Cf-python	netcdf4	pandas	requests	numpy	pytest
3.7.12	8.1.3	6.0	3.13.1	1.6.1	1.3.5	2.32.2	1.21.6	7.4.4
3.8.20	8.1.7	6.0.2	3.16.2	1.7.1	2.0.3	2.32.2	1.24.4	8.3.4
3.9.23	8.1.8	6.0.2	3.16.3	1.7.2	2.3.1	2.32.5	1.26.4	8.4.1
3.10.19	8.3.0	6.0.3	3.17.0	1.7.3	2.3.3	2.32.5	2.2.6	8.4.2
3.11.14	8.3.0	6.0.3	3.18.2	1.7.2	2.3.3	2.32.5	2.3.3	8.4.2
3.12.12	8.3.0	6.0.3	3.18.2	1.7.2	2.3.3	2.32.5	2.3.3	8.4.2
3.13.9	8.3.0	6.0.3	3.18.2	1.7.2	2.3.3	2.32.5	2.3.3	8.4.2
3.14.0	8.3.0	6.0.3	3.18.2	1.7.2	2.3.3	2.32.5	2.3.3	8.4.2

Also tested building upon jaspy 3.11/v20240815 and 3.12/v20250704 on JASMIN, all tests passed.

Note that as of writing, Python 3.14 has just been released, and Python 3.9 is about to go end-of-life.