Updated CI config

.gitlab-ci.yml

-image: debian:unstable
+image: docker.hacking.hu/public/sbt:latest
 
 before_script:
   - echo "deb http://172.16.0.19:9999/debian/ unstable main contrib non-free" > /etc/apt/sources.list
-  - apt-get update -y
-  - apt-get install -y gnupg2 apt-transport-https ca-certificates
-  - echo "deb https://dl.bintray.com/sbt/debian /" | tee -a /etc/apt/sources.list.d/sbt.list
-  - apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2EE0EA64E40A89B84B2DF73499E82A75642AC823
-  - apt-get update -y
-  - apt-get install -y openjdk-11-jdk-headless
-  - apt-get install -y sbt
+  - apt-get update -y && apt-get -y upgrade
 
 sget2:
   script: