fix: amend digest update workflow

geonetci has no ability to modify PR's and when run this way breaks the automation. it would be easier to manage if it makes multiple PR's than the current solution

.github/workflows/update-image-digests.yml

@@ -28,27 +28,13 @@ jobs:
           if git ls-files --others --modified --deleted --exclude-standard | grep -E 'config.yaml'; then
             echo "changes=true" >> $GITHUB_OUTPUT
           fi
-      - name: determine existing branch
-        id: branch
-        if: ${{ steps.determine-changes.outputs.changes == 'true' }}
-        run: |
-          TIMESTAMP="$(git log -n1 --pretty='format:%cd' --date=format:'%Y-%m-%d-%H-%M')"
-          NEW_BRANCH="config-yaml-image-update-for-${TIMESTAMP}"
-          EXISTING_BRANCH="$(gh pr list --label image-digest-update --json author,title,headRefName | jq -r '. | select(.[] | .title | contains("update sync config.yaml")) | select(.[] | .author.login | contains("github-actions[bot]")) | .[0].headRefName')"
-          if [ -n "$EXISTING_BRANCH" ]; then
-            NEW_BRANCH="$EXISTING_BRANCH"
-            echo "has-existing=true" >> $GITHUB_OUTPUT
-          fi
-          echo "timestamp=$TIMESTAMP" >> $GITHUB_OUTPUT
-          echo "new-branch-name=$NEW_BRANCH" >> $GITHUB_OUTPUT
       - name: commit and push if there are changes
         if: ${{ steps.determine-changes.outputs.changes == 'true' }}
         env:
-          TIMESTAMP: ${{ steps.branch.outputs.timestamp }}
-          NEW_BRANCH: ${{ steps.branch.outputs.new-branch-name }}
-          HAS_EXISTING: ${{ steps.branch.outputs.has-existing }}
           GH_TOKEN: ${{ secrets.GH_CI_USER_TOKEN }}
         run: |
+          TIMESTAMP="$(git log -n1 --pretty='format:%cd' --date=format:'%Y-%m-%d-%H-%M')"
+          NEW_BRANCH="config-yaml-image-update-for-${TIMESTAMP}"
           git add ./config.yaml
           git branch "${NEW_BRANCH}"
           git checkout "${NEW_BRANCH}"
@@ -58,8 +44,4 @@ jobs:
           if ! gh label list --json name --jq .[].name | grep -Eq '^image-digest-update$'; then
             gh label create image-digest-update || true
           fi
-          ACTION=create
-          if [ "$HAS_EXISTING" = true ]; then
-            ACTION=edit
-          fi
-          gh pr --label image-digest-update "$ACTION" --title "Update sync config.yaml images ${TIMESTAMP}" --body "updates sync config.yaml images for ${TIMESTAMP}"
+          gh pr --label image-digest-update create --title "Update sync config.yaml images ${TIMESTAMP}" --body "updates sync config.yaml images for ${TIMESTAMP}"