Added Opera "class" support version (#3102)
Added Opera "class" support version (#3102)

[classes.json](https://github.com/mdn/browser-compat-data/blob/master/javascript/classes.json#L53) shows that Opera 36 supports classes. This is mentioned in the Opera blog post for [version 36](https://dev.opera.com/blog/opera-36/#es6-block-scoped-bindings-in-sloppy-mode). Subclassing using Symbol.species support is described in detail in the blog post for [version 38](https://dev.opera.com/blog/opera-38/#es6-subclassing-using-symbolspecies). I'm not sure what to do with that information.
mdn/browser-compat-data,chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data