Option to specify EcmaScript version? #21
Description
I forgot I did this, but when running the fixer I had to specify in the parserOptions to run against the ES6 version due to several of our tests failing on ES5 which is the default. There are also options to use 7 and 8.
Should we add an option that allows the user to specify the Ecmascript version they want to run against? See https://eslint.org/demo/