ci: update Ruby versions

Author: kou

.github/workflows/pages.yml

@@ -26,7 +26,7 @@ jobs:
       - uses: actions/configure-pages@v5
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: "3.1"
+          ruby-version: ruby
       - uses: actions/cache@v4
         with:
           path: |

.github/workflows/test.yml

@@ -16,9 +16,9 @@ jobs:
       fail-fast: false
       matrix:
         ruby-version:
-          - "3.1"
           - "3.2"
           - "3.3"
+          - "3.4"
         runs-on:
           - macos-latest
           - ubuntu-latest