acme: fix RuboCop style.
acme: fix RuboCop style.

See https://github.com/Homebrew/brew/pull/7867.

Linuxbrew/homebrew-core,rwhogg/homebrew-core,maxim-belkin/homebrew-core,Linuxbrew/homebrew-core,rwhogg/homebrew-core,maxim-belkin/homebrew-core