change reviewers to assignees

Author: briandfoy

.github/workflows/new_pull_request.yml

@@ -20,4 +20,4 @@ jobs:
         perl .github/bin/labeler ${{ github.event.number }} add
     - uses: hkusu/review-assign-action@v1
       with:
-        reviewers: ${{ vars.ASSIGNEES }}
+        assignees: ${{ vars.ASSIGNEES }}