build: Remove root nuget.config file

[askpt]

This PR

This pull request removes custom NuGet package source configuration and related authentication from the CI/CD pipeline. The main change is the elimination of references to the GitHub-hosted NuGet feed for the open-feature organization, simplifying package management and build configuration.

CI/CD workflow simplification:

• Removed NUGET_AUTH_TOKEN environment variable and source-url pointing to the GitHub NuGet feed from the .github/workflows/ci.yml, .github/workflows/code-coverage.yml, .github/workflows/e2e.yml, and .github/workflows/release.yml workflows, so the builds now use only the default NuGet source. [1] [2] [3] [4] [5]

Configuration cleanup:

• Deleted the nuget.config file, which previously specified both the public NuGet feed and the GitHub-hosted feed, along with source mapping rules for OpenFeature packages.

Related Issues

Fixes #540

Notes

• This file and configurations are not needed. We don't consume any nuget package from the GitHub registry, we only push. So this configuration is not necessary and it will make the onboarding and actions easier.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.67%. Comparing base (5630d2b) to head (96d08ae).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #560   +/-   ##
=======================================
  Coverage   89.67%   89.67%           
=======================================
  Files          64       64           
  Lines        2509     2509           
  Branches      296      296           
=======================================
  Hits         2250     2250           
  Misses        199      199           
  Partials       60       60           

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[askpt]

/gemini review

[gemini-code-assist]

Code Review

This pull request correctly removes the nuget.config file, simplifying the build process. As noted in the review comment, the previous configuration had an ambiguous package source mapping which could lead to non-deterministic builds. Deleting the file is the right move to improve build reliability and maintainability.