Clasp deploy doesn't update the deployed version with Google Apps Script Web App

## Expected Behavior
Perhaps I'm misunderstanding, but from the readme I'd thought that `clasp deploy` would allow me to publish a new version of a Web App (in this case bound to a google sheet).

I'd expected the workflow to be as follows:

1. clasp version "My new version"
> Created version xx.
2. clasp deploy xx
> yyyyyyyyyyyyyyyyy @xx
3. clasp open
browser opens to newly published version "xx"

## Actual Behaviour
The version is created as expected, but the web app Project Version remains at the last deployed version not the version used with `clasp deploy`. To actually deploy it I have to go into the Script Editor then Publish > Deploy as Web App and then select the version "xx"

## Related Issues
This seems related to https://github.com/google/clasp/issues/43, however that issue specifically relates to Chrome store apps and this is a Web App which the comments on that issue suggest should be supported.