Create Dependabot config file (#1176)

👋 Dependabot is moving natively into GitHub! This pull request migrates your configuration from Dependabot.com to a config file, using the [new syntax](https://help.github.com/en/github/administering-a-repository/configuration-options-for-dependency-updates). When you merge this pull request, 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](https://github.com/NateRadebaugh/react-datetime/network/updates), rather than the [Dependabot dashboard](https://app.dependabot.com/), to monitor your version updates. Dependabot is now configured exclusively using config files.

Your previous schedule was set to `live`. This option is no longer supported in the new config file so it has been changed to `daily`.










If you've got any questions or feedback for us, please let us know by creating an issue in the [dependabot/feedback](https://github.com/dependabot/feedback) repository.

[Learn more about the relaunch of Dependabot](https://github.blog/2020-06-01-keep-all-your-packages-up-to-date-with-dependabot/)

Please note that regular `@dependabot` commands do not work on this pull request.

:robot::yellow_heart:

.github/dependabot.yml

@@ -0,0 +1,7 @@
+version: 2
+updates:
+- package-ecosystem: npm
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10