Remove no longer needed workaround

Author: eregon

dist/index.js

@@ -19,10 +19,6 @@ async function run() {
     if (platform === 'windows-latest') {
       rubyPrefix = await windows.downloadExtractAndSetPATH(ruby)
     } else {
-      if (ruby.startsWith('jruby')) {
-        // Workaround for https://github.com/actions/virtual-environments/issues/242
-        core.exportVariable('CLASSPATH', '')
-      }
       rubyPrefix = await downloadAndExtract(platform, ruby)
       core.addPath(`${rubyPrefix}/bin`)
     }