Travis build fails due to depreciated settings in the project-scratch-de.json

[djiwondee]

Found this issue while running the trailhead this repository is used for. The ./config/project-scratch-de.json-file contains setting that are depreciated in sfdx. As recommended in the log (which can be found in the Travis CI build section), the parameter orgPreferences:

{
    "orgName": "wade.wegner Example",
    "edition": "Developer",
    "orgPreferences" : {
        "enabled": ["S1DesktopEnabled"]
    }
}

must be changed with settings according to the following:

{
    "orgName": "wade.wegner Example",
    "edition": "Developer",
    "settings": {
        "lightningExperienceSettings": {
           "enableS1DesktopEnabled": true
        }
    }
}

Have seen the warning about the depreciated parameter for scratch org configs in the interactive exercises within the SFDX trailhead lessons already, but the build on travis-ci probably handles the parameter more restricted.