Update ruby binding deps, ruby gem version 0.2.3 (#374)

* Update ruby binding deps, ruby gem version 0.2.3

* and gem version to 0.2.3

* specify bunlder and rubygems version for CI

bindings/ruby/ext/regorusrb/src/lib.rs

@@ -1,4 +1,4 @@
-use magnus::{exception::runtime_error, method, module, prelude::*, Error, Ruby};
+use magnus::{Error, Ruby, exception::runtime_error, method, module, prelude::*};
 use regorus::Engine as RegorusEngine;
 use std::cell::RefCell;
 use std::cmp::Ordering;