Update sync-main-to-dev.yaml

Author: ralfhandl

.github/workflows/sync-main-to-dev.yaml

@@ -32,6 +32,7 @@ jobs:
         shell: bash
         run: |
           SYNC="$BASE-sync-with-$HEAD"
+          git fetch origin $HEAD $BASE
           git checkout -b $SYNC origin/$SYNC || git checkout -b $SYNC origin/$BASE
           git merge origin/$HEAD
           git checkout origin/dev src/*