Allow preLaunch task for compound list #45676
Description
Issue Type: Feature Request
Currently we can add a preLaunchTask prop to any launch setting. This works well when running a single project. But this get unworkable when using compounds.
When running multiple projects (website, API & CMS for example) in a compound launch task, triggering a build task from each preLaunchTask can throw an error about files being in use during buildtime. This happens when a buildable dependency is referenced from more than one project.
Can we allow compounds to have a preLaunchTask as well? Then we can trigger a global build and run all of the projects after the single build has succeeded. Much like the start command in Visual Studio on Windows works right now.
VS Code version: Code 1.21.0 (9a199d7, 2018-03-07T10:54:22.798Z)
OS version: Darwin x64 17.4.0