Task validation doesn't take into account multi-version extensions

[jessehouwing]

We publish the Azure DevOps Extension tasks with both the latest as well as older versions in the vsix, so for each task there can be multiple versions. This is done for backwards compat support for older Azure DevOps Server versions.

The extension therefore contains multiple task.jsons for each task

PublishExtension
\v4
   \task.json <- Node 10 & Node 16 support
\v5
   \task.json <- Node 16 and Node 20 support

But we still get a warning that PublishExtension\v4 depends on an older Node version.

From the perspective of the extension, the PublishExtension task supports the latest Task Handler.

Example here:
https://github.com/microsoft/azure-devops-extension-tasks/tree/main/BuildTasks/PublishExtension

I would not expect to see a deprecated runner warning for these tasks. And it should certainly not be turned into an error later on.