Staging workflow: await merge (#6309)

Author: hsubox76

.github/workflows/release-staging.yml

@@ -20,7 +20,7 @@ jobs:
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}
         script: |
-          github.rest.repos.merge({
+          await github.rest.repos.merge({
             owner: context.repo.owner,
             repo: context.repo.repo,
             base: 'release',