How to Include Custom Apps Located Inside a Folder in a Git Repo in apps.json for Docker Build?

I am setting up a Docker build workflow using apps.json to include custom apps. Currently, my apps.json looks like this:

[
  {
    "url": "https://github.com/frappe/payments",
    "branch": "develop"
  },
  {
    "url": "https://github.com/frappe/erpnext",
    "branch": "version-15"
  },
  {
    "url": "https://user:password@git.example.com/project/repository.git",
    "branch": "main"
  }
]

Now, I have a Git repository where the custom apps are organized inside a folder named apps. Each custom app resides in its own folder under the apps directory. For example:
repo/
├── apps/
│ ├── custom_app1/
│ ├── custom_app2/

I want to include these custom apps in apps.json for the Docker build workflow. How can I specify the path to these apps within the Git repository and ensure they are properly included during the build?