ci: Add Ruby 3.2/3.3/3.4 for CI

Signed-off-by: Kentaro Hayashi <[email protected]>

Author: kenhys

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [1.9, '2.0', 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.1, jruby-9.1, jruby-9.2]
+        ruby: [1.9, '2.0', 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, '3.0', 3.1, 3.2, 3.3, 3.4, jruby-9.1, jruby-9.2]
         gemfile: [no-deps, json-latest, json-old, json-pure]
         exclude:
           - ruby: '3.0'