Create version bump PRs in draft mode

Currently, the token we use to create these PRs doesn't have sufficient permissions to set off PR checks. Maybe if we create the PR as a draft and have a real person mark the PR as "ready-for-review", this will be enough to start PR checks.

.github/workflows/release.yml

@@ -129,6 +129,7 @@ jobs:
           body: This PR was automatically generated by the GitHub Actions release workflow in this repository.
           branch: ${{ format('version/bump-to-{0}', steps.bump-patch-version.outputs.next_version) }}
           base: main
+          draft: true
 
   vscode-publish:
     name: Publish to VS Code Marketplace