ci: add caching for NuGet packages in CI workflows

[askpt]

Signed-off-by: André Silva 2493377+askpt@users.noreply.github.com

This PR

This pull request enhances the CI/CD workflows by adding caching for NuGet packages across multiple workflow files. This change aims to improve build performance by avoiding repeated downloads of dependencies.

Workflow Improvements:

• .github/workflows/ci.yml: Added a step to cache NuGet packages in both the main CI job and another job within the same file. This uses the actions/cache action to store packages in ~/.nuget/packages and leverages file hashing for cache keys. [1] [2]
• .github/workflows/code-coverage.yml: Introduced NuGet package caching to the code coverage workflow, improving efficiency during the dotnet test step.
• .github/workflows/e2e.yml: Added caching for NuGet packages in the end-to-end testing workflow, reducing setup time for dependencies.
• .github/workflows/release.yml: Implemented NuGet package caching in the release workflow to optimize dependency installation during the dotnet restore step.

Notes

This is similar to open-feature/dotnet-sdk-contrib#453

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.35%. Comparing base (fbc2645) to head (a38b29d).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #522   +/-   ##
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  Coverage   87.35%   87.35%           
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  Files          47       47           
  Lines        1827     1827           
  Branches      190      190           
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  Hits         1596     1596           
  Misses        188      188           
  Partials       43       43           

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