Add the concourse release script JAR into the image

Author: Daniel Mikusa

ci/Dockerfile

@@ -1,6 +1,8 @@
 ARG base_image=ubuntu:bionic
 FROM ${base_image}
 
+ADD https://repo.spring.io/libs-release/io/spring/concourse/releasescripts/concourse-release-scripts/0.3.2/concourse-release-scripts-0.3.2.jar /opt/
+
 RUN apt-get update && apt-get install --no-install-recommends -y \
     ca-certificates \
     curl \