move to new base image
updated to agent 2.8.0.204-1.

Exact changelog unpublished. But this release skips

2.7.0.193-1:
  - When tailing the oplog, the agent no longer pre-fetches the next batch of oplog entries before exhausting the current batch.
  - Adds support for non-default Kerberos service names.
  - Adds support for RHEL7.