Using main branch of barge for tests (#464)

Author: jamiehewitt15

.github/workflows/tests.yml

@@ -37,7 +37,7 @@ jobs:
         with:
           repository: 'oceanprotocol/barge'
           path: 'barge'
-          ref: v4
+          ref: main
 
       - name: Login to Docker Hub
         if: ${{ env.DOCKERHUB_PASSWORD && env.DOCKERHUB_USERNAME }}