Drop JRuby 9.1 CI

Keep JRuby 9.2 CI as it passes.

Author: jeremyevans

.github/workflows/ci.yml

@@ -18,7 +18,6 @@ jobs:
         os: [ubuntu-latest]
         ruby: [ "2.0.0", 2.1, 2.3, 2.4, 2.5, 2.6, 2.7, "3.0", 3.1, 3.2, 3.3, 3.4, jruby-9.4 ]
         include:
-          - { os: ubuntu-22.04, ruby: jruby-9.1 }
           - { os: ubuntu-22.04, ruby: jruby-9.2 }
     runs-on: ${{ matrix.os }}
     name: ${{ matrix.ruby }}