using *zip*/archive.zip as default for :jenkins_artifact_file

deploy fails with `SSHKit::Runner::ExecuteError: Exception while executing on host <deploy host>: can't convert nil into String` when `:jenkins_artifact_file` not specified

using `*zip*/archive.zip` as default value

if `:jenkins_artifact_file` option not specified - unzipping artifact content and moving to release path.
It's been a little while since I was in here, but I think this `repo_path` is unnecessary, as this command is executed within the context of the current release. Still, if you've tested it & this works, great.