Remove unused function

#include <fmt/format.h>

#include <admire.hpp>

bool

string_to_convert(std::string s) {

    if(s == "true" || s == "TRUE" || s == "True") {

        return true;

    } else if(s == "false" || s == "FALSE" || s == "False") {

        return false;

    } else {

        throw std::invalid_argument(

                "ERROR: Incorrect input value. Please try again.\n");

    }

}

int

main(int argc, char* argv[]) {