[ci] Consider consistent Drake version pinning and/or canary builds

[EricCousineau-TRI]

At present, CMake can use latest nightly binaries, whereas Bazel is currently pinned.

Possible options for consistency:

• Use pinning for both CMake and Bazel. Make an explicit optional "canary" set of builds so that we can preview breakages as they come in.
  • This is similar to what we do in Anzu - explicit updates to Drake, but with canary integration CI to test Anzu master against Drake master.
  • Ideally, this setup should be applied to rolling builds too.
• Make both CMake and Bazel "bleeding edge" and require fixes, a la `drake-external-examples.

See @sloretz's additional notes here: https://github.com/RobotLocomotion/drake-ros/pull/242#pullrequestreview-1327327377