Skip test failing on JRuby on Windows

* See jruby/jruby#8623

Author: eregon

.github/workflows/test.yml

@@ -185,7 +185,8 @@ jobs:
       shell: bash
       run: echo ~ && bundle install
     - name: Windows JRuby
-      if: startsWith(matrix.os, 'windows') && startsWith(matrix.ruby, 'jruby')
+      # Should be startsWith(matrix.ruby, 'jruby') but broken on jruby-head: https://github.com/jruby/jruby/issues/8623
+      if: startsWith(matrix.os, 'windows') && matrix.ruby == 'jruby'
       run: gem install sassc
 
   testNoGemfile: