Invalid version check for mocha 10

[rickh18]

The version check in index.js is not valid for mocha 10+

 var version = json.version;
  if (version >= "6") {
    createStatsCollector = require("mocha/lib/stats-collector");
    mocha6plus = true;
  } else {
    mocha6plus = false;
  }

This will break the stats collector. Other functions work fine.