YEvent.changes typing is incomplete

[rideg]

Please save me some time and use the following template. In 90% of all issues I can't reproduce the problem because I don't know what exactly you are doing, in which environment, or which y-* version is responsible. Just use the following template even if you think the problem is obvious.

Checklist

• Are you reporting a bug? Use github issues for bug reports and feature requests. For general questions, please use https://discuss.yjs.dev/
• Try to report your issue in the correct repository. Yjs consists of many modules. When in doubt, report it to https://github.com/yjs/yjs/issues/

Describe the bug
YEvent.changes does not have typing for the keys property

To Reproduce
Try to run code completion in VSCode or with YouCompleteMe in Vi while using Typescript

Expected behavior
The keys property should be available for code completion

Screenshots

Environment Information
"yjs": "^13.3.2"

Additional context
Add any other context about the problem here.