Add Ruby 3.4 to CI

Author: jeremyevans

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ "1.9.3", "2.0.0", 2.1, 2.3, 2.4, 2.5, 2.6, 2.7, "3.0", 3.1, 3.2, 3.3, jruby-9.2, jruby-9.3, jruby-9.4 ]
+        ruby: [ "1.9.3", "2.0.0", 2.1, 2.3, 2.4, 2.5, 2.6, 2.7, "3.0", 3.1, 3.2, 3.3, 3.4, jruby-9.2, jruby-9.3, jruby-9.4 ]
     name: ${{ matrix.ruby }}
     env:
       BUNDLE_GEMFILE: .ci.gemfile