fixup! Upgrade minimum required Ruby to v3.1.2

Author: acant

.github/workflows/ci.yml

@@ -11,9 +11,9 @@ jobs:
         os: [ubuntu-latest, macos-latest]
         ruby: ['3.1', '3.2', '3.4', head]
         test_task: ['tests']
-      includes:
-        - ruby: 'head'
-          test_task: 'spec'
+        includes:
+          - ruby: 'head'
+            test_task: 'spec'
     continue-on-error: ${{ endsWith(matrix.ruby, 'head') || endsWith(matrix.ruby, 'jruby') }}
     runs-on: ${{ matrix.os }}
     steps: