title: Trigger VSTS pull request build verification based on path filter
body: <p>We have a repository with multiple projects. For example, one is an Angular project for the frontend, the other is an Azure Function for the backend.</p>
  
  <p>When code is pushed via pull request we have different builds that are triggered to verify the incoming changes.</p>
  
  <p>However, all of the verification builds are always triggered, even though changes are made to a single project, which resides in a specific directory (For example, only Angular coder is changed, all of it is under /Frontend path).</p>
  
  <p>There is one workaround I'm aware of - Splitting the repository in such way so there will be only a single project in each repository.</p>
  
  <p>This workaround is not suitable for my needs.</p>
  
  <p>Is there any other way to achieve this goal?</p>