TruffleRuby not supported on Windows

Exclude JRuby for now (ruby/setup-ruby#18)

Author: dentarg

.github/workflows/ruby.yml

@@ -13,6 +13,9 @@ jobs:
       matrix:
         os: [ ubuntu-latest, windows-latest ]
         ruby: [ 2.4, 2.5, 2.6, 2.7, jruby, truffleruby ]
+        exclude:
+          - os: windows-latest
+            ruby: [ jruby, truffleruby]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2