feat: add cling (#607)

README.md

@@ -132,6 +132,7 @@ Contributions are welcome. Please take a quick look at the [contribution guideli
  * [Athena Console](https://github.com/athena-framework/console) - Allows for the creation of CLI based commands
  * [clicr](https://github.com/j8r/clicr) -  A simple declarative command line interface builder
  * [clim](https://github.com/at-grandpa/clim) - Slim command line interface builder
+ * [Cling](https://github.com/devnote-dev/cling) - A modular, non-macro-based command line interface library
  * [commander](https://github.com/mrrooijen/commander) - Command-line interface builder
  * [Keimeno](https://github.com/robacarp/keimeno) -  A lightweight text user interface library in Crystal
  * [OptionParser](https://crystal-lang.org/api/OptionParser.html) - command-line options processing (Crystal stdlib)