Add eslint to every example missing it (vercel#172)

* Updated eslint version in places where it's used

* Added eslint-config-next where mising

* added eslint where missing

* Added a .eslintrc.json where needed

* Fixed multiple lint issues

* Fixed all known lint issues

* Fix lint issues on commit

* Add lint script to examples missing it

* Updated scripts in multiple examples

* Added prettier back where required

Author: lfades

Diff for: edge-functions/ab-testing-google-optimize/.eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "next/core-web-vitals"
+}

Diff for: edge-functions/ab-testing-google-optimize/components/layout.tsx

@@ -1,4 +1,4 @@
-import { FC, useCallback } from 'react'
+import { FC } from 'react'
 import Script from 'next/script'
 import { Layout, Page } from '@vercel/examples-ui'
 import type { LayoutProps } from '@vercel/examples-ui/layout'
@@ -16,10 +16,7 @@ function gaHandler() {
 }
 
 const OptimizeLayout: FC<LayoutProps> = ({ children, ...props }) => {
-  const ga = useCallback(
-    typeof window === 'undefined' ? throwIfSSR : gaHandler,
-    []
-  )
+  const ga = typeof window === 'undefined' ? throwIfSSR : gaHandler
 
   return (
     <Layout {...props}>