workspace_value_not_subdirectory

Workspace values must be a relative path of a subdirectory of '{0}'.

The analyzer produces this diagnostic when a workspace list contains a value that is not a subdirectory of the directory containing the `pubspec.yaml`` file.

The following code produces this diagnostic because the value in the workspace list is not a relative path of a subdirectory of the directory containing the 'pubspec.yaml' file:

name: example
workspace:
    - /home/my_package

Change the workspace list so that it only contains only subdirectory paths.

name: example
workspace:
    - pkg/package_1
    - pkg/package_2