deprecate --auto flag on replicated release create

[xavpaice]

The --auto flag is no longer needed since the config-based flow (.replicated file) provides the same defaults automatically. Mark the flag as deprecated and update the --confirm-auto help text to remove the explicit --auto reference.

Related PR: replicatedhq/replicated-docs#4110

New output:

~/go/src/github.com/replicatedhq/replicated/bin/replicated release create --auto
Flag --auto has been deprecated, use a .replicated file instead
Update available: v0.129.7
To upgrade, run "brew upgrade replicatedhq/replicated/cli"
  • Reading Environment ✓  

Prepared to create release with defaults:

    yaml-dir        "./manifests"
    promote         "update"
    version         "update-42e9bca-dirty"
    release-notes   "CLI release of update triggered by xavpaice [SHA: 42e9bca-dirty] [29 May 26 11:05 NZST]"
    ensure-channel  true
    lint-release    true

Create with these properties? (default Yes) [Y/n] n