Homebrew cask template uses deprecated `postflight`, warns on every `brew` invocation

[ubuntudroid]

build/brew/cq.rb.tpl:27 uses a postflight do block, which Homebrew has deprecated. On Homebrew 7.0.4, every brew outdated / brew upgrade run that touches the tap prints:

Warning: Calling `postflight` is deprecated! Use `postflight_steps` instead.
Please report this issue to the mozilla-ai/homebrew-tap tap (not Homebrew/* repositories), or even better, submit a PR to fix it:
  /opt/homebrew/Library/Taps/mozilla-ai/homebrew-tap/Casks/cq.rb:36

Because the cask is generated ("Auto-generated on release"), fixing the generated file in the tap would be overwritten on the next release — the template is the fix site.

The block only strips the quarantine attribute:

postflight do
  if OS.mac?
    system_command "/usr/bin/xattr", args: ["-dr", "com.apple.quarantine", "#{staged_path}/cq"]
  end
end

Two options:

1. Rename to postflight_steps, as the warning suggests.
2. Drop the block entirely in favour of the cask-level quarantine false stanza, if the intent is simply that the binary not be quarantined. This changes semantics — it prevents quarantining rather than removing the attribute afterwards — so it is your call which matches the intent.

Deprecations become errors in a later Homebrew release, at which point brew install cq / brew upgrade cq breaks rather than warns.

Environment: Homebrew 7.0.4, macOS 25.6.0 arm64, cq cask v0.17.0.