Update handbook with draft PRs

[reubano]

I removed it since the new github teams only allows draft PR on public repos. The docs need to be updated to make this distinction.

Original text

When you create a new branch in a project, you should immediately push that branch up to Github and create a Draft Pull Request. This allows co-workers and your boss to make comments on your code while you are writing it.

When you are ready to merge your code into the master branch, you change your Draft PR into a Pull Request (PR).