Minor changes to examples. Updating major semver updates with only `package.json` changes.
I've done my best to make sure that these packages.json files all have `latest` for the `nextjs` package, `cross-env` for those with `server.js` files, etc.
I also added a `package.json` to `with-dynamic-app-layout` (it was missing one previously)
Made sure to test all of these packages post-upgrade to ensure maintained functionality
I wrote a [script](https://github.com/j0lv3r4/dependency-version-updater) to update dependencies recursively in `package.json` files, e.g.:
```
$ node index.js --path="./examples" --dependencies="react=^16.7.0,react-dom=^16.7.0"
```
This PR contains the result against the examples folder.
