Use CSV for output tags of docker meta action in OCPP-tests (EVerest#…

…1049)

This has already been fixed in the reusable workflow ( EVerest/everest-ci#71 ) but this doesn't automatically apply here

Signed-off-by: Kai-Uwe Hermann <[email protected]>

.github/workflows/build_and_test.yaml

@@ -61,6 +61,7 @@ jobs:
         uses: docker/metadata-action@v5
         with:
           images: ${{ env.BUILD_KIT_IMAGE_NAME }}
+          sep-tags: ","
       - name: Set output tag
         id: buildkit_tag
         shell: python3 {0}