Better tests for today's date

[aburrell]

Description

Fixes a remaining part of #115 by ensuring a valid apex conversion takes place for today's date.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

import apexpy
import datetime as dt
import numpy as np

apex_out = apexpy.Apex(date=dt.datetime.utcnow(), refh=300)
np.isnan(apex_out.geo2apex(60, 15, 100)).any()

Results should be False

Test Configuration

• Operating system: OS X Big Sur
• Python version number: 3.9
• Compiler with version number: gfortran 12.2.0
• Relevant local setup details: N/A

Checklist

• [x] Make sure you are merging into the develop (not main) branch
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] Add a note to Changelog.rst, summarising the changes
• [x] Add yourself to AUTHORS.rst and .zenodo.json