[test] update apt repositories

.gitlab-ci.yml

@@ -10,6 +10,7 @@ build_test:
   image: 0xacab.org:4567/leap/bitmask-dev:latest
   stage: build
   script:
+    - apt-get -y update
     - apt-get -y install libappindicator3-dev libgtk-3-dev libzmq3-dev golang
     - mkdir -p /go/src/0xacab.org/leap/
     - ln -s "$(pwd)" ${APP_PATH}