Sbt-slave: enable Ubuntu package resolution via HTTPS

When building the sbt-slave Docker image, enable the resolution
of packages via HTTPS which is needed for SBT.

Change-Id: If9b4416de7c402624e6b749e84f872f293fd73d2
1 file changed
tree: 6e06521157716a4c6824ce0881113b2a3471f5e9
  1. jenkins/
  2. jenkins-docker/
  3. .gitignore