Minor tweaks for JSON schema regeneration PR

.github/workflows/regenerate-schemas.yml

@@ -32,9 +32,9 @@ jobs:
               git add libraries/core/dora-schema.json
               git config user.email "dora-bot@phil-opp.com"
               git config user.name "Dora Bot"
-              git commit -m "Update JSON schema for \`dora-core\`"
+              git commit -m "Update JSON schema for ${{ github.sha }}"
               git push -u origin HEAD
               git fetch origin main
-              gh pr create --fill
+              gh pr create --title "Update JSON schema for \`dora-core\`" --body "Update JSON schema for ${{ github.sha }}"
           fi