fix: codecov uploads failing

[dopry]

codecov uploads are failing due to rate limiting
see: https://github.com/jazzband/django-oauth-toolkit/actions/runs/16092121891/job/45410281627#step:8:37 codecov/feedback#735 (comment) indicated I should try oidc

Description of the Change

enable oidc on codecov step of test job.

Checklist

• PR only contains one change (considered splitting up PR)
• [N/A] unit-test added
• [N/A] documentation updated
• [N/A] CHANGELOG.md updated (only for user relevant changes)
• author name in AUTHORS

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.37%. Comparing base (8d3e7a9) to head (632f4d8).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1585      +/-   ##
==========================================
- Coverage   97.38%   97.37%   -0.01%     
==========================================
  Files          34       34              
  Lines        2214     2212       -2     
==========================================
- Hits         2156     2154       -2     
  Misses         58       58              

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[Copilot]

Pull Request Overview

Enable OpenID Connect (OIDC) for Codecov uploads to avoid rate limiting errors.

• Grant id-token: write permission for OIDC token retrieval
• Upgrade codecov-action from v3 to v5 and enable use_oidc: true

Comments suppressed due to low confidence (2)

.github/workflows/test.yml:9

• When you define a custom permissions block, it overrides defaults like contents: read. Add contents: read alongside id-token: write so actions/checkout and other steps still have repository read access.

    permissions:

.github/workflows/test.yml:65

• [nitpick] Consider pinning to a specific patch release (e.g., @v5.3.1) instead of the floating @v5 tag to avoid unexpected breaking changes from future updates.

      uses: codecov/codecov-action@v5

[dopry]

@n2ygk I'd love to get this merged if you're okay with it so I can get pending PRs rebased on it to assert coverage changes.