Tweak matrix

Author: Matt Muller

.github/workflows/ci.yml

@@ -22,10 +22,12 @@ jobs:
             gemfile: json-old
           - ruby: 3.1
             gemfile: json-old
-          - ruby: 1.9
-            gemfile: json-latest
-          - ruby: 1.9
-            gemfile: json-pure
+          - ruby: 3.2
+            gemfile: json-old
+          - ruby: 3.3
+            gemfile: json-old
+          - ruby: 3.4
+            gemfile: json-old
 
     steps:
       - name: Setup Ruby