RequiredRuntimeAttribute is ignored and could be deleted

[rainersigwald]

msbuild/src/Framework/RequiredRuntimeAttribute.cs

Lines 10 to 18 in 4618ab5

	/// <summary>
	/// When marked with the RequiredRuntimeAttribute, a task indicates that it has stricter
	/// runtime requirements than a regular task - this tells MSBuild that it will need to potentially
	/// launch a separate process for that task if the current runtime does not match the version requirement.
	/// This attribute is currently non-functional since there is only one version of the CLR that is
	/// capable of running MSBuild v2.0 or v3.5 - the runtime v2.0
	/// </summary>
	[AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
	public sealed class RequiredRuntimeAttribute : Attribute

This is part of the public API surface, but is used in only one place in our repo

msbuild/src/Tasks/GenerateResource.cs

Lines 55 to 56 in 4618ab5

	[RequiredRuntime("v2.0")]
	public sealed partial class GenerateResource : TaskExtension, IIncrementalTask

And doesn't seem to be respected anywhere (e.g. nothing inspects for that attribute and behaves differently).

I think it's an older design for what eventually got implemented with UsingTask/magic task parameters for runtime, and could be removed.