attempt to fix submodule updates

Author: bradh352

.github/workflows/sync_upstream.yml

@@ -29,10 +29,13 @@ jobs:
         run: |
           git config --global user.name '[github actions]'
           git config --global user.email 'bradh352@users.noreply.github.com'
+          git pull
           cd src/sonic-swss
           git checkout master-broadcom
+          git pull
           cd ../sonic-sairedis
           git checkout master-broadcom
+          git pull
           cd ../..
           git add .
           git commit -am "update sonic-swss and sonic-sairedis branches"