[pchalamet]

Align local builds and all four GitHub Actions workflows on .NET SDK 10.0.401, and upgrade MongoDB.Bson from 3.6.0 to 3.12.0 consistently across the library and tests.

Update FsUnit to 8.0.0, NUnit to 5.0.0, NUnit3TestAdapter to 6.3.1, and Microsoft.NET.Test.Sdk to 18.11.0. Update the README SDK requirements and Unreleased changelog.

Validation:

• Debug and Release solution builds passed with zero warnings or errors across net10.0, net9.0, net8.0, and netstandard2.1.
• All 78 tests passed in both Debug and Release on .NET 10.
• Release NuGet packaging succeeded; package dependency metadata was inspected.
• NuGet reported no known vulnerabilities, including transitive dependencies.
• Changelog gate and git diff --check passed.

Consumers now require MongoDB.Bson 3.12.0 or newer and should align MongoDB.Driver accordingly. MongoDB.Driver 3.10 and newer require MongoDB Server 4.4 or newer. Runtime tests cover .NET 10; other library targets were compile-checked.

[github-actions]

Test Results (PR)

78 tests   78 ✅  0s ⏱️
 1 suites   0 💤
 1 files     0 ❌

Results for commit 77cd955.