Auto assign PR to author

[Matt711]

Description

I think most PRs remain unassigned, so this PR auto assigns the PR to the PR author. I think this will help keep our project boards up-to-date.

Checklist

• [ ] I am familiar with the Contributing Guidelines.
• [ ] New or existing tests cover these changes.
• [ ] The documentation is up to date with these changes.

[bdice]

@vyasr You were interested in increasing automation. What do you think of this proposal?

[Matt711]

/merge