infrastructure: Unpin cf-deployment
infrastructure: Unpin cf-deployment

- Previously we pinned to a major version of cf-deployment. Instead
  we will now float on the latest available release.
- This has the advantage of not requiring a manual bump when
  cf-deployment cuts a major release.
- This is a trade-off against possibly seeing more failures due to
  breaking changes in cf-deployment.

[#166010822](https://www.pivotaltracker.com/story/show/166010822)

cloudfoundry/cli,cloudfoundry/cli,cloudfoundry/cli