* update Microsoft.Extensions.FileProviders.Embedded v7.0.1 => v7.0.2 
* update Microsoft.Extensions.Localization v7.0.1 => 7.0.2 
* update Axuno.VirtualFileSystem v2.0.0 => v2.0.1
* bump to v2.0.1

* Add net80 as target framework
* Update nuget packages to latests
* Update unit test to use the constraint model
* Bump version to v2.1.0

See also axuno/VirtualFileSystem#6

**Library Project:**
- Scriban.Signed v5.10.0 -> 6.2.1 (breaking)
- Axuno.VirtualFileSystem v2.1.0 -> 2.2.0
- Microsoft.Extensions.FileProviders.Composite v8.0.0 -> v9.0.6
- Microsoft.Extensions.FileProviders.Embedded v8.0.6 -> v9.0.6
- Microsoft.Extensions.FileProviders.Physical v8.0.6 -> v9.0.6
- Microsoft.Extensions.Localization v8.0.6 -> v9.0.6
- System.Collections.Immutable v8.0.6 -> v9.0.6

**Unit Tests:**
- Microsoft.NET.Test.Sdk v17.10.0 -> v17.14.1
- Microsoft.Extensions.DependencyInjection v8.0.0 -> 9.0.6
- NUnit v4.1.0 -> v4.3.2
- NUnit3TestAdapter v4.5.0 -> v5.0.0
- NUnit.Analyzers v4.2.0 -> 4.9.2

Bump version to `v3.0.0`

**CI Build**
Update `build_test.yml` to use `ubuntu-22.04` instead of `ubuntu-latest` because of missing libssl failure with `ubuntu-24.04`

…#10)

chore: Updated `Scriban` from v6.2.1 to v6.4.0 and other referenced nuget packages