fix pr_body for auto generated PR

.github/workflows/release-pdf-converter.yml

@@ -116,5 +116,5 @@ jobs:
         destination_branch: master
         pr_title: Prepare pdf-converter v${{ steps.package-json.outputs.packageVersion }}
         pr_label: flag/exclude-from-changelog,type/prepare-next-version
-        pr_body: "An automated PR generated by ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/actions/runs/${GITHUB_RUN_ID}"
+        pr_body: "An automated PR generated by ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
         github_token: ${{ secrets.GITHUB_TOKEN }}