[CI] Use Codecov token

[giordano]

No description provided.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 42.20%. Comparing base (b6ffc96) to head (177e03f).
⚠️ Report is 1432 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1585       +/-   ##
===========================================
+ Coverage   21.66%   42.20%   +20.53%     
===========================================
  Files          46      123       +77     
  Lines        8048    21797    +13749     
===========================================
+ Hits         1744     9200     +7456     
- Misses       6304    12597     +6293     

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[giordano]

The post above is the proof this is working 🙂

[giordano]

Just as a further confirmation this worked, the merge commit of this PR is the first commit to have coverage data in codecov in 10 months: https://app.codecov.io/gh/EnzymeAD/Reactant.jl/commits