function is never used in build

[mikemadden42]

$ rustc --version
rustc 1.52.1 (9bc8c42bb 2021-05-09)

$ sw_vers
ProductName:    macOS
ProductVersion: 11.3.1
BuildVersion:   20E241

I see this warning from cargo build --release:

warning: function is never used: `configuration`
  --> src/banner.rs:29:8
   |
29 | pub fn configuration(mode: &str, url: &str, threads: &str, wordlist: &str) -> String {
   |        ^^^^^^^^^^^^^
   |
   = note: `#[warn(dead_code)]` on by default

warning: 1 warning emitted