chore: Upgrade dependencies

[kailash-b]

✏️ Changes

GitHub Actions (CI workflows):

• codecov/codecov-action 6.0.1 → 7.0.0
• actions/checkout 6.0.3 → 7.0.0
• snyk/actions/dotnet 0.4.0 → 1.0.0
• actions/setup-dotnet 5.3.0 → 6.0.0

Applied across build.yml, nuget-release.yml, release.yml, rl-secure.yml, and snyk.yml.

NuGet packages:

• Microsoft.AspNetCore.Authentication.JwtBearer 8.0.27 → 8.0.29 (patch)
• Microsoft.SourceLink.GitHub 10.0.300 → 10.0.301 (patch)
• Microsoft.NET.Test.Sdk 18.5.1 → 18.8.1 (minor, test project only)

Keeping dependencies current reduces security exposure and keeps the build/release pipeline on supported action versions.

🔗 References

This PR bundles and supersedes the following individual Dependabot PRs (closed automatically on merge):

• Closes chore: Bump codecov/codecov-action from 6.0.1 to 7.0.0 #69 — codecov/codecov-action 6.0.1 → 7.0.0
• Closes chore: Bump actions/checkout from 6.0.3 to 7.0.0 #74 — actions/checkout 6.0.3 → 7.0.0
• Closes chore: Bump snyk/actions/dotnet from 0.4.0 to 1.0.0 #78 — snyk/actions/dotnet 0.4.0 → 1.0.0
• Closes chore: Bump actions/setup-dotnet from 5.3.0 to 6.0.0 #80 — actions/setup-dotnet 5.3.0 → 6.0.0
• Closes chore: Bump Microsoft.AspNetCore.Authentication.JwtBearer from 8.0.27 to 8.0.29 #81 — Microsoft.AspNetCore.Authentication.JwtBearer 8.0.27 → 8.0.29
• Closes chore: Bump Microsoft.SourceLink.GitHub from 10.0.300 to 10.0.301 #83 — Microsoft.SourceLink.GitHub 10.0.300 → 10.0.301
• Closes chore: Bump Microsoft.NET.Test.Sdk from 18.5.1 to 18.8.1 #84 — Microsoft.NET.Test.Sdk 18.5.1 → 18.8.1

🎯 Testing

• This change adds unit test coverage
• This change adds integration test coverage
• This change has been tested on the latest version of the platform/language or why not — verified via existing CI (build + unit tests) passing on the updated versions

✅ Checklist

• I have read the Auth0 general contribution guidelines
• I have read the Auth0 Code of Conduct
• All existing and new tests complete without errors
• All commits are signed.