update codecov action

[d-chambers]

Description

This PR updates the codecov action to version 4 and configures the actions to use the dascore token so that coverage will again be reported in PRs.

Checklist

I have (if applicable):

• referenced the GitHub issue this PR closes.
• documented the new feature with docstrings or appropriate doc page.
• included a test. See testing guidelines.
• your name has been added to the contributors page (docs/contributors.md).
• added the "ready_for_review" tag once the PR is ready to be reviewed.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.52%. Comparing base (38eed62) to head (01bf3a4).

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #370       +/-   ##
===========================================
+ Coverage        0   99.52%   +99.52%     
===========================================
  Files           0       94       +94     
  Lines           0     7415     +7415     
===========================================
+ Hits            0     7380     +7380     
- Misses          0       35       +35     

Flag	Coverage Δ
unittests	99.52% <ø> (?)

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