Approve submission PRs before auto-merging

This change to the "Manage PRs" workflow will cause the "github-actions" bot to add an approval pull request review to
submission PRs after they have passed all compliance checks, but before merging.

This is necessary to allow us to instate the "Require pull request reviews before merging" branch protection rule on
`main`, which will protect the repository from accidental pushes by the maintainers and administrators with write
permissions in the repository.

As an added benefit, this will more clearly indicate the status of a submission in the case where it is fully compliant
with the Library Manager requirements but an automated merge is not possible due to a merge conflict. In this case, the
bot will add an approval each time the workflow is triggered, but that is a reasonable behavior, and one permitted by the
PR review system (i.e., subsequent approvals will not cause a spurious workflow run failure, with either workflow trigger
event type).

.github/workflows/manage-prs.yml

@@ -342,6 +342,17 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Approve pull request
+        uses: octokit/request-action@v2.x
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          route: POST /repos/{owner}/{repo}/pulls/{pull_number}/reviews
+          owner: ${{ github.repository_owner }}
+          repo: ${{ github.event.repository.name }}
+          pull_number: ${{ github.event.pull_request.number }}${{ github.event.issue.number }}
+          event: APPROVE
+
       - name: Merge pull request
         uses: octokit/request-action@v2.x
         env: