Bump CI matrix

Author: numbata

.github/workflows/ci.yml

@@ -43,10 +43,9 @@ jobs:
           - { ruby: '3.3', grape: '2.2.0' }
           - { ruby: '3.4', grape: '2.2.0' }
           - { ruby: 'head', grape: '2.2.0' }
-          # - { ruby: '3.1', grape: 'HEAD' }
-          # - { ruby: '3.2', grape: 'HEAD' }
-          # - { ruby: '3.3', grape: 'HEAD' }
-          # - { ruby: '3.4', grape: 'HEAD' }
+          - { ruby: '3.2', grape: 'HEAD' }
+          - { ruby: '3.3', grape: 'HEAD' }
+          - { ruby: '3.4', grape: 'HEAD' }
     name: test (ruby=${{ matrix.entry.ruby }}, grape=${{ matrix.entry.grape }})
     runs-on: ubuntu-latest
     needs: ['rubocop']