Upgrade to GitHub-native Dependabot#11

_Dependabot Preview will be shut down on August 3rd, 2021. In order to keep getting Dependabot updates, please merge this PR and migrate to GitHub-native Dependabot before then._ Dependabot has been fully integrated into GitHub, so you no longer have to install and manage a separate app. This pull request migrates your configuration from Dependabot.com to a config file, using the [new syntax][new_syntax]. When merged, we'll swap out `dependabot-preview` (me) for a new `dependabot` app, and you'll be all set! With this change, you'll now use the [Dependabot page in GitHub][dependabot_page], rather than the [Dependabot dashboard][dashboard], to monitor your version updates, and you'll configure Dependabot through the new config file rather than a UI. Your account was configured to allow an unlimited number of open pull requests. This option is no longer supported in the new config file so it has been changed to `99`. If you've got any questions or feedback for us, please let us know by creating an issue in the [dependabot/dependabot-core][issues] repository. [Learn more about migrating to GitHub-native Dependabot][learn] Please note that regular `@dependabot` commands do not work on this pull request. [dashboard]: https://app.dependabot.com/ [dependabot_page]: https://github.com/Kikobeats/css-urls/network/updates [issues]: https://github.com/dependabot/dependabot-core/issues/new?assignees=%40dependabot%2Fpreview-migration-reviewers&labels=E%3A+preview-migration&template=migration-issue.md [learn]: http://docs.github.com/code-security/supply-chain-security/upgrading-from-dependabotcom-to-github-native-dependabot [new_syntax]: https://help.github.com/en/github/administering-a-repository/configuration-options-for-dependency-updates [org_secrets_url]: https://github.com/settings/secrets/dependabot [repo_secrets_url]: https://github.com/Kikobeats/css-urls/settings/secrets/dependabot