Fix the standalone build and add compatibility tests - #131

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-dotnet@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Argument of type '(string, string?, bool)[]' cannot be used for parameter 'expected' of type 'IEnumerable<(string, string, bool)>' in 'void ShouldBeTestExtensions.ShouldBe<(string, string, bool)>(IEnumerable<(string, string, bool)>? actual, IEnumerable<(string, string, bool)>? expected, bool ignoreOrder = false)' due to differences in the nullability of reference types.

Argument of type '(string, string?, bool)[]' cannot be used for parameter 'expected' of type 'IEnumerable<(string, string, bool)>' in 'void ShouldBeTestExtensions.ShouldBe<(string, string, bool)>(IEnumerable<(string, string, bool)>? actual, IEnumerable<(string, string, bool)>? expected, bool ignoreOrder = false)' due to differences in the nullability of reference types.