Support for custom package.json properties to write changelist entries

[ggrafhalfbrick]

Unity supports a custom tag in the package.json file to show current version information directly in their Unity package manager.
That property looks like this:
"_upm": {
"changelog": "- Fixed1 \n - Fixed2 \n - New feature 3"
},

Is there any way we can make npm also write the release-notes into a property that we can configure in the same step as it writes the version number?