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.
* replace componentWillReceiveProps by componentDidUpdate
* replace props.url by withRouter HOC
* fix deprecated `props.url` in with-shallow-routing example
* Examples: clarify language around Yarn create & npx
* add missing READMEs and create-next-app usage
* suggest people tag jthegedus in firebase related issues
* add yarn alt instructions
* cerebraljs example readme & fixes
* remove global npm install of create-next-app
* add npx to create-next-app command in examples
* add bash to shell snippets
* add yarn create to next-app command in examples
* fix READMEs named with lowercase
* change READMEs to use UPPERCASE
* Simplify route info handling.
* Add basic resolve=false support.
* Make sure to render getInitialProps always if it's the first render.
* Change resolve=false to shallow routing.
* Add test cases for shallow routing.
* Update README for shallow routing docs.
* Update docs.
* Update docs.
* Update docs.
