Fix badges

[WilliamJamieson]

I noticed that some of the badges in the readme are broken. This PR fixes that.

Tasks

• Update or add relevant roman_datamodels tests.
• Update relevant docstrings and / or docs/ page.
• Does this PR change any API used downstream? (If not, label with no-changelog-entry-needed.)
  • Write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see below for change types).
  • Start a romancal regression test (https://github.com/spacetelescope/RegressionTests/actions/workflows/romancal.yml) with this branch installed ("git+https://github.com/<fork>/rad@<branch>").

News fragment change types:

• changes/<PR#>.feature.rst: new feature
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.doc.rst: documentation change
• changes/<PR#>.removal.rst: deprecation or removal of public API
• changes/<PR#>.misc.rst: infrastructure or miscellaneous change

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.59%. Comparing base (087a60d) to head (746b05e).
⚠️ Report is 190 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #570      +/-   ##
==========================================
- Coverage   97.56%   95.59%   -1.97%     
==========================================
  Files          30       40      +10     
  Lines        2788     4155    +1367     
==========================================
+ Hits         2720     3972    +1252     
- Misses         68      183     +115     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[braingram]

Thanks!