Catch Erfa warnings

[wtbarnes]

Fixes #89

This PR catches the Erfa warnings that are raised when we convert the times from the error and degradation tables into UTC while making them astropy.time.Time objects.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (e578cdf) 94.14% compared to head (e00317a) 94.09%.
Report is 2 commits behind head on main.

❗ Current head e00317a differs from pull request most recent head 406a473. Consider uploading reports for the commit 406a473 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #324      +/-   ##
==========================================
- Coverage   94.14%   94.09%   -0.05%     
==========================================
  Files          34       34              
  Lines        1178     1186       +8     
==========================================
+ Hits         1109     1116       +7     
- Misses         69       70       +1     

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[nabobalis]

Need to wait for any online tests to check.