Drop JRuby and TruffleRuby from CI

RBS has a C extension that cannot build on JRuby/TruffleRuby.
Use `engine: cruby` to restrict the test matrix to CRuby only.

Author: st0012

.github/workflows/test.yml

@@ -16,6 +16,7 @@ jobs:
     with:
       min_version: 3.2
       versions: '["mswin"]'
+      engine: cruby
 
   test:
     needs: ruby-versions
@@ -25,14 +26,6 @@ jobs:
         ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
         os: [ubuntu-latest, macos-latest, windows-latest]
         exclude:
-          - os: windows-latest
-            ruby: truffleruby
-          - os: windows-latest
-            ruby: truffleruby-head
-          - os: windows-latest
-            ruby: jruby
-          - os: windows-latest
-            ruby: jruby-head
           - os: macos-latest
             ruby: mswin
           - os: ubuntu-latest