Migrate Renovate configuration from package.json to .github/renovate.json

[oscard0m]

Renovate is deprecating the usage of its configuration inside package.json. We should move the configuration to .github/renovate.json

There are 2 octoherd scripts already in place to do the migration:

• https://github.com/octoherd/script-setup-renovate
• https://github.com/oscard0m/octoherd-script-remove-renovate-package.json

You can read more about this in Probot and Octokit projects:

• How is Probot project managing dependency updates? probot/probot#1725 (reply in thread)
• add renovate configuration to Repository if repository is in @octokit octokit/create-octokit-project.js#98