One way to solve this is using the clientResourceRelativePath that can be configured in your module.config.
Look for the heading "Versioning client resources" in Configuring shell modules.
I also realized that we have an example of one way to automate this: https://github.com/episerver/AddOn.Favorites/
There is this msbuild task that will create a nuget package containing the addon as a zip file that will contain directories that is versioned.
Have can I force the client browser to download the latest copy of the MyProperty.js?
The .js is not in a bundle and I cannot add a querystring to the reference as the file is never referenced in a classic way.
I've built a Custom Dojo widget and placed it at \ClientResources\Scripts\Editors\MyProperty.js together with a html-template and a CSS.
In my module.config I have:
And I've added a EditorDescriptor: