FIX use extra MQTT broker as step instead action

.github/workflows/functional.yml

@@ -27,12 +27,12 @@ jobs:
         ports:
           - 27017:27017
 
-      mosquitto-extra:
-        # Needed by MQTT notification tests (multi broker)
-        #image: eclipse-mosquitto:2.0.11
-        image: eclipse-mosquitto:1.6.15
-        ports:
-        - 1884:1883
+      #mosquitto-extra:
+      #  # Needed by MQTT notification tests (multi broker)
+      #  #image: eclipse-mosquitto:2.0.11
+      #  image: eclipse-mosquitto:1.6.15
+      #  ports:
+      # - 1884:1883
 
     name: functional - ${{ matrix.payload.name }}
 
@@ -56,7 +56,13 @@ jobs:
       - name: Run Mosquitto container with authenticated user
         # Why don't to use a service for this (as moquitto-extra above)? It would be the desirable solution, but I haven't able to
         # configure volumes properly for it (the mosquitto container as service has problems to get the configuration files). Feedback welcome! :)
-        run: docker run -d --name mosquitto -p 1883:1883 -v $(pwd)/test/functionalTest/mosquittoConf:/mosquitto/config eclipse-mosquitto:2.0.11
+        run: docker run -d --name mosquitto -p 1883:1883 -v $(pwd)/test/functionalTest/mosquittoConf:/mosquitto/config:ro eclipse-mosquitto:2.0.11
+
+      - name: Run Extra Mosquitto container used in multibroker tests
+        # Note we are reusing the same volume (although the extra broker does not require authenticated user). We use a service in the past
+        # to implement this (using eclipse-mosquitto:1.6.15) but in eclipse-mosquitto:2.0.11 it seems something in the internal configuration
+        # has changed and it doesn't work if we don't provide the configuration files in the volume. Again, feedback is welcome! :)
+        run: docker run -d --name mosquitto -p 1883:1883 -v $(pwd)/test/functionalTest/mosquittoConf:/mosquitto/config:ro eclipse-mosquitto:2.0.11
 
       - name: Run functional test
         run: |