Previews are not available on Windows

Author: eregon

.github/workflows/test.yml

@@ -23,12 +23,14 @@ jobs:
         - { os: windows-2019, ruby: mswin }
         exclude:
         - { os: windows-2016, ruby: 1.9 }
+        - { os: windows-2016, ruby: 3.1 }
         - { os: windows-2016, ruby: debug }
         - { os: windows-2016, ruby: truffleruby }
         - { os: windows-2016, ruby: truffleruby-head }
         - { os: windows-2016, ruby: truffleruby+graalvm }
         - { os: windows-2016, ruby: truffleruby+graalvm-head }
         - { os: windows-2019, ruby: 1.9 }
+        - { os: windows-2019, ruby: 3.1 }
         - { os: windows-2019, ruby: debug }
         - { os: windows-2019, ruby: truffleruby }
         - { os: windows-2019, ruby: truffleruby-head }