Update yarn.lock if package.json has been updated

This doesn't have to be done by the bot since it can run after CI but just wanted to note it here.

https://github.com/devtools-html/debugger.html/blob/master/bin/update-yarn-lock-file

Start by reading package.json and the referenced bin/update-yarn-lock-file script from devtools-html/debugger.html, then inspect how this bot runs after package changes. Done means an updated package.json is followed by a refreshed yarn.lock without requiring the bot to perform the work during the initial change.

Written by the indexing model from the issue text.