Update front branch to 2.0.x in QA workflow

Author: botisSmile

.github/workflows/qa.yml

@@ -18,7 +18,7 @@ jobs:
         uses: actions/checkout@v3
         with:
           repository: 'Elastic-Suite/gally-admin'
-          ref: main
+          ref: 2.0.x
           path: front/gally-admin
       - name: Cache Composer dependencies
         uses: actions/cache@v4