Is your feature request related to a problem? Please describe.
Sometimes PRs are opened without an adequate description. This makes it hard for reviewers to review the PR.
Describe the solution you'd like
Oppiabot should reassign the PR back to the author if the PR description is not filled in. (It's fine to use #N/A for point 1 if there's no issue number, but point 2 should always be fully filled in.)