chore: Update repo-sync.yml (#878)

Author: sichanyoo

.github/workflows/repo-sync.yml

@@ -14,12 +14,9 @@ jobs:
         uses: actions/checkout@v4
         with:
           ref: main
-      - name: Add staging repo as remote
+      - name: Add staging repo as remote with token
         run: |
-          git remote add staging-repo https://github.com/awslabs/private-smithy-swift-staging.git
-      - name: Set up auth
-        run: |
-          git config --global url."https://${{ secrets.REPO_SYNC_AUTOMATION_USER_TOKEN }}@github.com".insteadOf "https://github.com"
+          git remote add staging-repo https://${{ secrets.REPO_SYNC_AUTOMATION_USER_TOKEN }}@github.com/awslabs/private-smithy-swift-staging.git
       - name: Push changes to staging repo
         run: |
           git push staging-repo main