Use RabbitMQ 3.7.8 in CI, use Package Cloud to install

Author: acogoluegnes

.travis.yml

@@ -13,14 +13,13 @@ addons:
     sources:
       - sourceline: deb https://packages.erlang-solutions.com/ubuntu trusty contrib
         key_url: https://packages.erlang-solutions.com/ubuntu/erlang_solutions.asc
-      - sourceline: deb https://dl.bintray.com/rabbitmq/debian trusty main
-        key_url: https://dl.bintray.com/rabbitmq/Keys/rabbitmq-release-signing-key.asc
     packages:
-      - esl-erlang=1:20.1
+      - esl-erlang=1:20.3
 # because of https://github.com/travis-ci/travis-ci/issues/8906
 before_install:
+  - curl -s https://packagecloud.io/install/repositories/rabbitmq/rabbitmq-server/script.deb.sh | sudo bash
   - sudo mv /opt/jdk_switcher/jdk_switcher.sh /tmp
-  - sudo apt-get install rabbitmq-server=3.7.1-1
+  - sudo apt-get install rabbitmq-server=3.7.8-1
   - sudo mv /tmp/jdk_switcher.sh /opt/jdk_switcher/
 services:
   - rabbitmq