Update after-validate-submission.yaml

adding git pull

Author: shauntruelove

.github/workflows/after-validate-submission.yaml

@@ -100,6 +100,7 @@ jobs:
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git pull origin main
           if [ -n "$(git status --porcelain)" ]; then
             git add model-output/hub-ensemble/*
             git commit -m "Upload new files to RSV data repo by ${GITHUB_ACTOR} in #${{ github.event.pull_request.number }}"