This update allows for cases where the app is within a folder within a DMG where the distribution requires the parent folder containing the app needs to be copied to the destination, not just the app itself (should also work for ZIP but I haven't come across an example where this would be required).

Example:
AppName.dmg when mounted contains a folder AppFolderName which contains the app bundle but also other related content (companion apps, settings etc)
When mounted the folder structure will be /Volumes/AppName/AppFolderName/AppName.app
This change will let you specify AppFolderName in the label. Verification will still occur on AppName.app after which AppFolderName and its contents will be copied into place.

Changes are:

• New label property folderName
• Update to installAppWithPath to take a folderPath argument. Will still perform all the same checks on $appPath but instead of ditto -v "$appPath" to install the app it performs ditto -v "$folderPath"
• Function installFromDMG() updated to handle folderPath

As written, installFromDMG will always pass in two arguments to installAppWithPath. The check in installAppWithPath will verify if it has an actual value or "$dmgmount/ with no folder path by looking for a trailing /. Optionally could make installFromDMG only pass the argument if required but we are doing the verification anyway.

Also, this change will preserve removing of the app bundle if an earlier version exists, but does not remove the parent folder. This is partially intentional as there may be app configuration however it may be desirable to either allow (or explicitly disallow) removal of the parent folder during an update. In testing the current behaviour didn't present an issue though.

Included in the PR is a label for an app where this is the case (ChemDoodle) but the format would look something like:

applabel)
     name="AppName"
     type="dmg"
     downloadURL="https://some/url/AppName.dmg"
     expectedTeamID="ABC1234"
     folderName="AppFolderName"
     appName="${folderName}/AppName.app"
     appNewVersion=$(...)
     ;;

Tested with ChemDoodle and also verified this should not break any existing functionality (not in the labels I tested at least)