ci: bump test image tag from 3.4-rc to 3.4

Author: flavorjones

.github/workflows/ci.yml

@@ -20,8 +20,8 @@ on:
 jobs:
   ruby_versions:
     outputs:
-      setup_ruby: "['3.1', '3.2', '3.3', 'head']"
-      image_tag: "['3.1', '3.2', '3.3', '3.4-rc']"
+      setup_ruby: "['3.1', '3.2', '3.3', '3.4']"
+      image_tag: "['3.1', '3.2', '3.3', '3.4']"
     runs-on: ubuntu-latest
     steps:
       - run: echo "generating rubies ..."
@@ -361,7 +361,7 @@ jobs:
           - { ruby: "3.2", flavor: "alpine3.19" }
           - { ruby: "3.3", flavor: "alpine3.18" }
           - { ruby: "3.3", flavor: "alpine3.19" }
-          - { ruby: "3.4-rc", flavor: "alpine" }
+          - { ruby: "3.4", flavor: "alpine" }
     runs-on: ubuntu-latest
     container:
       image: ruby:${{matrix.ruby}}-${{matrix.flavor}}