Migrate to @babel/eslint-parser

[pdewouters]

I ran into an issue with eslint which led me to the solution - which is to use @babel/eslint-parser instead of babel-eslint which is deprecated. Note that I had to also set BABEL_ENV = development in the script command https://babeljs.io/blog/2020/07/13/the-state-of-babel-eslint

This fixes the issue when I run the linter locally, but the linter bot fails because our library doesn't have @babel/eslint-parser and @babel/eslint-plugin

@kadamwhite how could I test this to make it more likely to get merged without breaking anything?