13 jobs still use EOL xenial base images

[tfoote]

Following #877

Already Failing

• [x] doc_independent #877
• [ ] doc_rosindex
  • [x] https://github.com/ros2/ros2_documentation/pull/1518
  • [x] https://github.com/ros-infrastructure/rosindex/pull/268
  • [ ] https://github.com/hidmic/sphinx-tabs/pull/1

Not yet failing

• [x] ci_create_reconfigure_task https://github.com/ros-infrastructure/ros_buildfarm/pull/906
• [x] devel_create_reconfigure_task https://github.com/ros-infrastructure/ros_buildfarm/pull/906
• [x] doc_create_reconfigure_task https://github.com/ros-infrastructure/ros_buildfarm/pull/884
• [x] doc_metadata_task https://github.com/ros-infrastructure/ros_buildfarm/pull/884
• [x] rosdistro_cache_task https://github.com/ros-infrastructure/ros_buildfarm/pull/886
• [x] release_check_sync_criteria_task https://github.com/ros-infrastructure/ros_buildfarm/pull/886
• [x] release_create_reconfigure_task https://github.com/ros-infrastructure/ros_buildfarm/pull/886
• [x] release_create_trigger_task https://github.com/ros-infrastructure/ros_buildfarm/pull/886
• [x] blocked_releases_page_task https://github.com/ros-infrastructure/ros_buildfarm/pull/885
• [x] blocked_source_entries_page_task https://github.com/ros-infrastructure/ros_buildfarm/pull/885
• [x] release_compare_page_task https://github.com/ros-infrastructure/ros_buildfarm/pull/885
• [x] release_status_page_task https://github.com/ros-infrastructure/ros_buildfarm/pull/885

[nuclearsandwich]

@tfoote Propose deprecation note hidmic/sphinx-tabs#1 is the only outstanding TODO on this issue. Since the rosindex job is running (now no longer on Xenial) is that work still required before we can close this one out?

[tfoote]

Yeah we can close this out now. The sphinx-tabs us removed now: https://github.com/ros-infrastructure/rosindex/pull/268 so the deprecation note is valuable but not necessary for our purposes now.