DOC: update numpy versions in test case examples

[jo-mueller]

Updated environment names in contribution guide

Hi there, first-timer here :) I went to go through the doc pages for contributing and tried running the test commands outlined there:

...
hatch env run --env test.py3.12-2.1-optional run-coverage
...

which leads to an error (Unknown environment: test.py3.12-2.1-optional) since the test matrix is specified with numpy 2.2:

[[tool.hatch.envs.test.matrix]]
python = ["3.11", "3.12", "3.13"]
numpy = ["1.26", "2.2"]
deps = ["minimal", "optional"]

So I just changed the example commands in the doc pages to work right away with the current pyproject.toml. It's a tiny little change but hopefully makes the entrance for some a little easier if they haven't worked with hatch, etc before.

Thanks for considering!

[d-v-b]

thanks for this!