CI: fix docker-compose not found error

* Change branch Incorrect type from string to array
* update docker-compose command to docker compose

.github/workflows/tests.yml

@@ -3,6 +3,7 @@
 # This file is part of Invenio.
 # Copyright (C) 2016-2024 CERN.
 # Copyright (C) 2022 Graz University of Technology.
+# Copyright (C) 2024 KTH Royal Institute of Technology.
 #
 # Invenio is free software; you can redistribute it and/or modify
 # it under the terms of the MIT License; see LICENSE file for more details.
@@ -11,9 +12,11 @@ name: CI
 
 on:
   push:
-    branches: master
+    branches:
+      - master
   pull_request:
-    branches: master
+    branches:
+      - master
   schedule:
     # * is a special character in YAML so you have to quote this string
     - cron:  '0 3 * * 6'
@@ -66,7 +69,7 @@ jobs:
           pip install ".[$EXTRAS]"
           pip freeze
           docker --version
-          docker-compose --version
+          docker compose --version
 
       - name: Run tests
         run: ./run-tests.sh