title: Manage dependencies of git submodules with poetry
body: <p>We have a repository <em>app-lib</em> that is used as sub-module in 4 other repos and in each I have to add all dependencies for the sub-module.
  So if I add/remove a dependency in <em>app-lib</em> I have to adjust all other repositories. 
  I there a way to tell Poetry to install the root repo dependencies and the ones in the sub-module?</p>
  
  <p>The <code>my-package = { path = "../my-package/dist/my-package-0.1.0.tar.gz" }</code> parameter seems only to work for files. And I don't know if it's good design to store all wheels in <em>app-lib</em>.</p>
  
  <p>I kind of want to merge the root toml file dependencies and the sub-module toml file dependencies and then install them.</p>
  
  <p>Thanks</p>