Upgrade eslint and other packages once eslint bug is fixed

[vincerubinetti]

Big babel-eslint issue causing false positives for the no-unused-vars rule:
eslint/eslint#12117

This issue is a reminder/tracker to update react-scripts, eslint, and any other packages that are out-of-date or that were version locked to work-around this error.

Also, remove eslint from dependencies and peerDependencies.

[vincerubinetti]

eslint and babel-eslint were fixed a couple of days ago, but I was waiting on create-react-app to be updated as well because it includes those two packages in (I think) pinned versions.

But for the heck of it I tried removing the manual eslint pin from my package.json, and updating all the packages, and it doesn't throw the false positive error anymore. Either I was wrong and create-react-app specifies a non-pinned/latest version of estlint and so it was automatically a non-issue, or the newer fixed version of eslint is being specified from some other package and overriding the broken version in create-react-app.

[vincerubinetti]

I am dumb. I think it was my own hetio frontend-components with the eslint pin that was preventing the error. So even though I removed the eslint pin from this repo and it worked fine, I'm not considering this fixed yet.

Looks like create-react-app really needs to fix this upstream ASAP.