Removed the duplicated strategies

Author: hsbt

.github/workflows/test.yml

@@ -21,8 +21,6 @@ jobs:
         os: [ 'ubuntu-latest', 'windows-latest' ]
         include:
           - { os: macos-latest, ruby: '2.6' }
-          - { os: ubuntu-latest, ruby: 'jruby-head' }
-          - { os: ubuntu-latest, ruby: 'jruby-9.2' }
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v3