ci: let pre-commit-autoupdate create prs in draft mode

[afuetterer]

Description

At the moment the pre-commit PRs do not trigger checks, which is not ideal, because the updates could lead the failing tests.

This PR updates the pre-commit-autoupdate job to create PR in draft mode. Once a draft PR is set to "ready for review" by a RMDO contributor, the additional CI checks will run on that PR.

Motivation and Context

See above.

How has this been tested?

In my fork of the project.

Types of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Checklist

• I have read the contributor guide.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[MyPyDavid]

thanks @afuetterer, makes sense!